Acros blocklock-zs66 headset lower part, so suitable for frames that require a ZS66 lower press fit cup, as found on various big hitting E-Bikes, such as Giant Reign and Nukeproof Neutron.

Comes with clever 'block lock' crown race, with fits the larger variety 1.8inch steerer fork. The block lock element allows the forks to move freely and then provides a 'stop', in order to prevent the bars swinging around and hitting the frame in the event of an off.

It is also possibly to source an Acros 1.5inch crown race, which would then effectively allow the use of a standard tapered steerer fork in a 66 intended frame......which is what I run. To be clear, this option isnt included, but worth mentioning, as I really struggled to find a suitable solution until I came across this make.