Use ball bearing bullet blocks to lead control lines with a minimum of friction. A wide range of variations let these versatile blocks adapt to almost all control lines situations. Wire bullet blocks use higher load carrying roller bearing, and feature Teflon impregnated hardkote anodized aluminum sheaves. Use for halyards and other small boat wire controls. 5/16 in LINE, MWL 400#, BS 2000# WT.21/4OZ SHEAVE 11/8".