The Summit Machine Large Flex Joint is our most popular size joint we make. The related dimensions for many builds became industry standards. 3.125″ OD, 2.625″ mounting width and a 5/8″ (16mm) bore. This style joint is machine from a solid piece with an 1-1/4″-12 LH shank. A rebuildable spherical joint for the builder looking for quality. The Summit Machine Flex Joint was developed in 2004 and only keeps getting better. You will not find a higher quality, better functioning “Cartridge Style” joint than the Summit Machine Flex Joint. These joints meet or exceed expectations in performance, reliability and durability. Many success stories of this joint lasting 75,000 and even 100,000 miles or more! Joint specs: – (Weld on) Housing is un-plated DOM for easy welding. – (Billet) Housing is zinc plated after being beautifully machined to added rust and corrosion protection. Machined with precision and exacting standards with threads complying with ANSI standards. – Races are machined from an engineered plastic complete with grease grooves in the race concavity. These grooves keep grease surrounding the ball and ensure they are nice and quiet. No more squeaky heims! – Center pivot ball machined from mild steel with a smooth nickel plating for even wear with races and added rust prevention. – Flat washer and machined threaded retaining ring yellow zinc plated for corrosion resistance.