Strong strap padded with vinyl tubing with control bar attachments at each end. One end has a quick release for emergencies (pull the red ball). The 'U' shape created allows you to hook into a harness hook.  Also called a 'D-loop' since it forms a 'D' shape  when attached to the bar.    It's about 24" (61 cm) long between webbing connection straps. 

Note: Hooking into a kite can be dangerous. This is recommended for experienced riders only.