BY FAR the DURABLE longest lasting NON-oring 219 chain. For lightest "RACING" chain DID HTZ, lowest maintenance (can't adjust length) is RK/DID oring, CZ falls between DID and Panther, Fastech-Racing tested this chain using a PRD Fireball TAG package and racked up OVER 50+ hours and two full rebuilds on ONE chain, believe it or not! Also proven durable for E-bike applications by multiple bike manufacturers, used for Surron #219 conversions, etc. FTP Adjustable Chain Tool recommended for wider heavy-duty #219 chains.