TufForce 1" Tube Ring or Mount, MT-25T4B, Clamp on Scope, Shotgun 1" barrel or Magazine tube, patent granted Fit for 1" Scope Tubes or Barrel or Mag. tube, Such as Remington 870,1100,11-87 SP-10, Mossberg 500 835 Maverick 88Winchetser 1300 ATTENTION : make sure the diameter of tube/barrel is 1", if it is less than 1" you can try to add spacer at your own risk 4 slots, 45mm / 2" length, Just 2 screws tighten on the neck and Can be Mounted at Any Angle Precision Machined Out of Premium 6061 Aircraft Aluminum; Black Hard Anodized Finish