variable diameter stabilizer, API 7-1 standard variable diameter stabilizer, specifications: 1. API 7-1 Spec 2. 8 3/ 4" ~ 8 1/ 2" or as per your request 3. Variable diameter stabilizer solves the problem which common stabilizer can' t solve Variable Diameter stabilizer is one of main drill tool assembly in hole guiding. During drilling in deviating and horizontal well, in view of workmanship, stabilizer OD is required to be equal or 1~ 2mm less than drill bit so that too small clearance between borehole wall and stabilizer usually causes stabilizer to be easily stuck during tripping out of hole. However, variable diameter stabilizer solves the problem which common stabilizer can' t solve. During drilling in directional well, by use of differential pressure at nozzle produced by circulation of fluid among inside and outside of drilling string, stabilizer stretch out supporting head to reach full hole so that stabilizer equipped with different drill tools to increase or angle drop or stabilizer hole inclination. Meanwhile, when stop pump circulation, support head draw back so that stabilizer OD becomes small to improve tripping out smoothly. Welcome your inquiry.