HOIST FITNESS HD 3100 PREACHER CURL/ TRICEP EXTENSION COMMERCIAL GYMPreacher Curl Triceps Extension HD 3100 The HOIST Preacher Curl Triceps Extension with its bi directional arm and multiple range of motion adjustments allows for performance of both biceps and triceps exercises all in one machine. Multiple grip options and seven seat adjustments for varying user heights also comes standard with this machine. The HD 3100 is part of HOISTs HD Dual Series line, offering a comprehensive solution for fitness facilities