The 35 mm film gauge has long been the most common gauge in professional usage, and thus enjoys the greatest number of cameras currently available for professional usage. The modern era of 35 mm cameras dates to 1972, when Arri's Arriflex 35BL and Panavision's original Panaflex models emerged as the first self-blimped, lightweight cameras. Another distinguishing characteristic of modern cameras is the adoption of stronger lens mount seatings secured with a breech lock – namely the Arri PL and PV mount, both of which were designs descended from the BNCR mount of Mitchell cameras.