Written and maintained by CASRAI Editorial Board
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This page describes products and general use; it is not medical advice.
A G-tube button is a low-profile gastrostomy feeding device that sits flush against the abdomen and is used with a detachable extension set for feeding. It is specified by two numbers, a French size (diameter) and a stoma tract length in centimetres, and by its balloon fill volume. This page explains the parts, how sizes are written, and what comes in a kit, using two manufacturers’ published datasheets. It is written for clinic staff, buyers and students; a clinician chooses and fits the device for each patient.
What a G-tube button is
A G-tube button (also called a low-profile gastrostomy tube or gastrostomy button) is a gastric feeding device used with a stoma, the opening into the stomach. Feeding happens through a separate extension set that connects to the button’s port. The Compat Buddy datasheet describes its button as intended for patients who need intermittent or continuous enteral administration of nutrition, fluids or medication at the gastric site, and also suitable for gastric decompression. For the broader picture, see what a feeding tube is; for the nose-to-stomach alternative, see the nasogastric tube guide.
Who uses it: patients on long-term gastric feeding, their caregivers, and the clinicians, nurses and supply staff who order and fit the devices.
Parts and build
The parts below are taken from the Compat Buddy datasheet (AXI00044 Rev.3, April 2024), a balloon-retained silicone button. Other brands differ in detail.
- Feeding port with anti-reflux valve: purple on this model; accepts straight and right-angle extension sets.
- Cap: marked with the French size and length of the button.
- Inflation valve: a Luer connector marked with the balloon volume in mL.
- Balloon: a high-resistance silicone balloon, filled through the inflation valve.
- Radio-opaque stripe: shows on imaging.
- Recessed distal tip: the end inside the stomach is recessed.
The tube is silicone. The manufacturer states the device is sterile (ethylene oxide), individually packed, for single use, with a 3-year shelf life, and that DEHP and BPA are not intentionally added and it is not formulated with natural rubber latex.
Types and variants
| Variant | Typical use | Key difference | Source |
|---|---|---|---|
| Gastric balloon button | Feeding, fluids or medication into the stomach; also gastric decompression | Single gastric port; balloon retention | Compat Buddy datasheet |
| Gastric-jejunal (G-J) button | Feeding into the jejunum with a separate gastric port | Has both a gastric and a jejunal port, each needing its own feed or extension set; jejunal tube lengths of 15, 22, 30 and 45 cm; never cut to custom lengths | AMT G-JET brochure |
| Full kit (Compat “Buddy Kit”) | Button plus accessories | Button, 2 ENFit extension sets, 35 mL ENFit syringe, 10 mL Luer syringe, stylet, water-soluble lubricant, 2 gauze pads | Compat Buddy datasheet |
| Compact kit (Compat “Buddy Compact Kit”) | Button plus essentials | Button, 10 mL Luer syringe, stylet, water-soluble lubricant, 2 gauze pads; no extension sets or ENFit syringe listed | Compat Buddy datasheet |
| Legacy vs ENFit connector sets | Matching the feed or extension set to the button | AMT sells both legacy and ENFit extension and feed sets; ENFit kits carry an “-I” suffix on the order number. ENFit is a registered trademark of GEDSA. | AMT G-JET brochure |
Brand-specific size tables (for example for Mic-Key buttons) are published by their own manufacturers; this page gives values only for the two documents cited below.
Sizes and what the numbers mean
A button is ordered by French size and stoma tract length. French size (Fr, F or FR) is the tube size. Compat’s ordering tables express length as the stoma tract length in centimetres, and the cap is marked with both the French size and the length, for example “18 Fr, 1.5 cm”. This is how a G-tube size chart is organised: the Compat ordering tables list stoma tract length down the side and French size across the top.
| Manufacturer and product | French sizes | Length range |
|---|---|---|
| Compat Buddy (gastric) | 12, 14, 16, 18, 20, 24 FR | 0.8 to 6.5 cm stoma tract length; the longest lengths (6.0 and 6.5 cm) appear only for some French sizes |
| AMT G-JET (gastric-jejunal) | 14, 16, 18 F | Stoma lengths of 1.0 to 5.5 cm in its table, with jejunal tube lengths of 15, 22, 30 or 45 cm |
Balloon fill volume by French size
Each manufacturer publishes its own volumes. Values below are in mL of water, from the two documents.
| French size | Compat Buddy recommended / maximum | AMT G-JET minimum / recommended / maximum |
|---|---|---|
| 12 | 3.0 / 5.0 | not listed |
| 14 | 4.0 / 6.0 | 3 / 4 / 5 |
| 16 | 5.0 / 7.0 | 3 / 4 / 5 |
| 18 | 5.0 / 7.0 | 7 / 8 / 9 |
| 20 | 8.0 / 12.0 | not listed |
| 24 | 8.0 / 12.0 | not listed |
Are G-tube sizes the same across brands? The French size means the same thing, but the available lengths and the balloon volumes differ. At 14 Fr, Compat recommends 4.0 mL with a 6.0 mL maximum, while AMT’s G-JET lists 4 mL recommended and 5 mL maximum; at 18 Fr the two tables differ more. The AMT brochure notes that the recommended volume is printed on the fill valve of each button. Never apply one brand’s volume to another.
How to choose
The manufacturers’ documents state these points:
- AMT states that to ensure a proper fit it is crucial to measure the stoma length using its Balloon Stoma Measuring Device, so length is measured, not assumed.
- Compat states its document does not replace the original Instructions for Use, which must be read before use.
- AMT advises consulting a healthcare provider before adjusting the fill volume.
- For a gastric-jejunal button, AMT states the ports need different feed or extension sets, so stock for both must be matched to the device.
Choosing the type, size and length for a person is a clinician’s decision.
Safe use and handling basics
- Follow the manufacturer’s Instructions for Use for the specific model; this page is not a substitute.
- The Compat button is labelled single use, with storage in the original packaging at room temperature, in a dry place, away from direct sunlight and heat.
- Check the expiry date on the package; Compat states a 3-year shelf life from production.
- Use the fill volume printed on the button’s valve rather than a number from another product.
- Keep extension sets matched to the button’s connector type (legacy or ENFit).
Common mistakes
- Treating a size chart from one brand as valid for another.
- Ordering by French size alone without the stoma tract length.
- Assuming a compact kit includes extension sets; the Compat compact kit contents list does not.
- Cutting a G-J button to length; AMT states these should never be cut.
- Using a gastric feed set on the jejunal port of a G-J button; AMT states different sets are required for each port.
FAQ
What do numbers like “18 Fr 1.5 cm” mean?
The first number is the French size; the second is the stoma tract length in centimetres. Both are marked on the cap of the Compat Buddy button.
Is a button the same as a G-tube?
A button is one kind of gastrostomy tube: a low-profile one that sits against the skin and uses a detachable extension set for feeds.
Are G-tube sizes the same across brands?
French sizes are comparable, but lengths offered and balloon volumes are brand-specific, as the table above shows.
What is in a G-tube button kit?
It varies by kit. The Compat full kit lists the button, two ENFit extension sets, a 35 mL ENFit syringe, a 10 mL Luer syringe, a stylet, lubricant and two gauze pads. Its compact kit lists the button, Luer syringe, stylet, lubricant and gauze.
Sources
- Compat, “Full Range of Low-profile Gastrostomy Feeding Tubes” (Buddy), datasheet AXI00044 Rev.3, 18 April 2024. compat.com datasheet. Date checked: 2026-10-30.
- Applied Medical Technology, G-JET Button brochure C-4497-M (2025). appliedmedical.net brochure. Date checked: 2026-10-30.
Both sources are manufacturer documents, so they describe those makers’ own products. Related CASRAI reading: how gauge sizing works for IV catheters, what a 10 mL syringe is and how a collection kit contents list is laid out.
