The Z-RAM steel buttstock adapter fits all named Umarex T4E HDB68/TB68 versions and provides a direct rear connection for an HPA bottle. An 88 g CO2 capsule requires the separate intermediate adapter, and installation requires a careful cutout in the marker's rear plastic cover.
Two gas routes, one marker-side adapter
For HPA, the buttstock adapter provides the marker-side connection for a standard compatible bottle. For an 88 g CO2 configuration, the product description requires a separate intermediate adapter between this part and the capsule. That intermediate component is sold separately and must not be assumed to be in the box.
The supplied item is one burnished-steel buttstock adapter with an integrated O-ring. Its listed length is 7 cm, and the description identifies a dual-diameter form of 1.5 cm and one inch.
Fit is confirmed for HDB68/TB68
HDB68 and TB68 are equivalent names for the same model family when the model number and .68 caliber match. The product record states that the adapter works with all HDB68 versions. That does not make it a universal T4E stock adapter for HDR, HDS, HDX or TC platforms.
The permanent-looking part of the installation
The rear plastic cover on the HDB68/TB68 needs a cutout to accommodate the adapter. Although the steel adapter can be removed, the cover modification remains visible. Measure and plan against the current product geometry before any cutting, and use qualified help if you cannot make a clean, controlled opening.
This guide does not provide cutting dimensions because the product record does not define a universal template. Improvised dimensions could damage the cover or create poor alignment.
View the exact buttstock adapter
BUTTSTOCK ADAPTER HDB68 UMAREX T4E Serie
Why it belongs: It is the exact marker-side adapter for the two gas routes explained in this guide.
Decision boundary: The 88 g route needs a separately sold intermediate adapter, and the rear cover needs a cutout.
View the HDB68/TB68 AdapterComplete the system without duplicate purchases
- Included: one steel buttstock adapter with integrated O-ring.
- Required for the 88 g route: the separate intermediate adapter and the correct 88 g capsule arrangement.
- Required for HPA: a compatible rated bottle and regulated supply.
- Installation prerequisite: the controlled rear-cover cutout.
If you are also considering a performance component, keep that decision separate. The Z-RAM compatibility guide helps verify each interface rather than treating a complete build as one untested claim.
What the adapter does not prove
The part confirms a mechanical gas-source connection on the HDB68/TB68. It does not guarantee a Joule value, establish a regulator setting or prove that every bottle is suitable. Those choices require their own ratings, instructions and controlled verification.
Important Legal Notice
Laws and regulations governing the purchase, possession, installation, modification, and use of the products described on this page vary by country, state, and local jurisdiction and may change. Before purchasing, installing, modifying, or using any product, you are responsible for confirming that it is permitted in your location and for your intended purpose. Product availability or delivery does not mean that purchase, possession, installation, modification, or use is lawful in your jurisdiction. Z-RAM does not provide legal advice, and the information on this page must not be treated as legal advice. If you are unsure, contact the competent local authority or a qualified legal professional.