This is a professional grade screen rolling tool with wood handle primarily used for installing aluminum or fiberglass screen fabric into window screens and screen doors. Designed for production usage, it is a specialized combination rolling tool with a 2-1/2 inch x 1/16 inch convex steel roller and ball-bearing hub at one end and a 2 inch x 3/32 inch concave steel roller and ball-bearing hub at the opposite end. To be used with vinyl screen spline sizes 0.115 inch up to 0.165 inch