The Kirk MPA-2 Monopod Head was designed & built in the USA & is constructed from tough 6061-T aircraft aluminium including the solid, captive-design knobs, & the internal metal parts are stainless steel to avoid corrosion. The bearings are made from self-lubricating Delrin composite, & the tripod socket accepts 3/8-inch thread. The Kirk MPA-2 features Kirk's 2.5-inch Arca-style quick release body/lens clamp, so you can upgrade your system to quick-release immediately. The MPA-2 has robust locking nut design allowing you to easily operate even while wearing gloves. The design is so strong it holds & locks down 80lbs of camera & lens gear.