Nylon construction but very sturdy, comes with all the fittings.  An excellent price/performance hop unit.  Arm pin is metal and rotary wheel has the right amount of tension.  Includes a smaller barrel spring and a free ZCI shore 60 silicon bucking and nub.  Uses the concave style hop arm design, good for Omega nubs etc.

A worthy addition is the XT addon pack which includes a better barrel clip, stablising ring and spring.
https://www.ak2m4.co.uk/xt-rotary-hop-chamber-addons

I recommend using a tiny amount of silicon grease on the wheel where it meets the oring.