Real Avid Smart Fit Vise Block Sleeve, Fits AR10, Red AVAR10SFVBS The Smart-Fit Vise Block Sleeve for AR10 is an innovative product that allows you to work on large frame AR's with precise fit and zero wobble. It is designed to slide over the existing Real Avid Smart-Fit AR15 Vise Block and eliminates any wiggle or movement while working on the firearm. The sleeve can be used with an inverted lower receiver to work on pistol grips or allow easy access to the underside of your AR. It is a must-have tool for securing an AR when swapping trigger groups" servicing the lower receiver" installing grips and buffer tubes" or easily cleaning the barrel bore.