RAM Mount RAM Double Ball Mount w/1/4"-20 Male Thread - Medium Arm [RAM-101AU]RAM Double Ball Mount with 1 4" 20 Male Thread Medium Arm The RAM 101AU consists of a double socket arm mount, one round 2. 5" diameter base with the universal AMPS hole pattern and round base with a 1 4" 20 threaded steel stud. The round base provides support and stability for cameras that rest on top of it. The male 1 4" 20 threaded steel stud will connect to any standard female thread found on camcorders and digital cameras. Hole Pattern: 4 Hole