The Tii-On Double Dynamic Block measures 20mm and boasts a stainless-steel head loop for maximum strength and reliability. It is available with or without a Tii-Shackle and should be attached by feeding the rope around the central axle and through the head of the block, with a crossed/through threaded line preferred for double blocks. The block's design also includes a large central rivet for lightweight and rope-friendly attachment, as well as our patented bearing system for superior load-carrying ability and longevity. Compatible with 1.5mm Kiteline Dyneema and 2mm Dyneema. For expert fitting advice, please contact us.