Sprite Science Aluminum Size 8mm SHF8 SK8 Linear Rod Rail Shaft Support (SK8,Pack of 10) Linear Rail Shaft Support;Total Size : 4.1 x 1.4 x 3.3cm / 1.6" 0.55" x 1.3"(L*W*T) Shaft Inner Dia : 8mm/ 0.31";Material : Aluminum Mounting Hole Dia : 5.5mm/ 0.22" Hole Spacing : 33mm/ 1.3" Package Content : 10pcs Linear Rail Shaft Support