The cheekplate revolves around the sheave axle allowing the block to open; a safety ball stops the block from opening with an adjustable screw to set the ball on locked position.
There is a becket for the "hanging line".

MATERIAL: sheave with composite fibre main bearing and double side ball bearing. Hard anodized and teflon coated aluminium cheekplates with side rubber protections (yellow rubber on the revolving cheekplate). Standard model can be attached with highly resistant Dyneema/spectra line.