Saber Tactical FX Impact TRS Standard 12.5 inch extension Integrated bubble level M-Lok accessory slots 20 MOA elevation Delrin shroud clamp to prevent shroud droop Black anodized finish Weight: 1lb Attach the Saber Tactical Top Rail Support (TRS) to your FX Impact to mount accessories like the GRS Top Mounted Bipod. Featuring an integrated bubble level at the rear of the rail and 20 MOA elevation, this is the perfect FX Impact accessory for long range shooting. Please Note: This rail is NOT compatible with the FX Impact M4 air rifle