For use with 1/2-inch ultrasonic horn, 9814-25, and 1/4-inch or 1/2-inch extenders, only. Both slide adapters have a #36 Screw thread at top with a 6-inch extension, either 25 mm O.D. for insertion into a #25 Screw thread or 35 mm O.D. for use in a #36 Screw thread. Secure 1/2-inch horn in adapter with 7506 bushing and o-ring, then slide adapter extension into thread on reaction vessel, again securing with 7506 bushing. Now you have a variable depth adjustment of horn to achieve greater efficiency. Complete item consists of adapter, one nylon bushing with one FETFE o-ring.