Used on the following models:

Matrix Fitness
G3-FW52-03 | Back Extension Bench | G3FW52 | 2013
G3-FW52-03 | G3FW52E, G3FW52F | Back Extension Bench
MG-A52 | Back Extension Bench | FW334 (JIS) / FW511 (JIV) | 2019
MG-A52 | Back Extension Bench | FW334B | 2019