the Volume Soft Lock is simple but crucial to retain your volume adjustment. This 3D printed Volume Lock is made from PETG and has been thoroughly tested for strength and durability. Simply slide the lock one way or the other to lock/unlock your volume adjustment. When finished using the radio, remove the lock and store separately. Since the lock is fitting over the antenna, the maximum antenna diameter is 14.5mm, .57", or 9/16 of an inch. We are working on locks to work with larger diameter antenna but this gives you a general guideline.