This is a tool that we use for protecting the block when removing the anti-tamper screws on Kral air rifles.

Many models are fitted with an anti-tamper shear bolt for one of the barrel screws and one of the valve housing screws. Generally these are drilled and then tapped to remove. However when drilling it is very easy to damage the block as drill bits tend to slip off. We have had these stainless steel drilled through guide screws made to reduce this risk. They screw in ontop of the grub screw and guide the drill bit helping to stop it sliding off and protecting the block if it does. After making a small hole in the anti-tamper bolt, the tool can be removed and generally an old allen key tapped into this hole and unscrewed. Make sure not to drill through too far or you will drill completely through the anti tamper and damage the internal parts of the rifle.

Replacements grub screws for the anti-tamper ones are available here for the barrel and it is the same part also for the valve housing.