Ko-ken Ratchets Ko-ken ratchets are known for their very low backlash, small head sizes, and high torque ranges. We designed the new 72 tooth ratchet without compromising on our traditional strengths. The patented design of the 72T combines the low backlash, small size, and has a 10% higher torque limit in comparison to the 36 tooth ratchet. The legacy 36 tooth ratchets move 10/click. The new 72 tooth ratchets move 5/click. The design changes include moving from the single pawl of the 36 tooth design to the patented dual pawl of the 72 tooth design. The dual pawl 72 tooth design utilizes a single spring. We took four years of testing to perfect the low spring pressure needed to maintain Ko-ken's hallmark low-torque backlash. The finer 72 teeth design creates more surface area contact with the gear; thus, it has a 10% higher torque upper limit. The 72T is being released in the Z-Series 3/8" ratchets only in 2021. We will be releasing the 72T in OE" and oe" sizes, without compromising the body sizes and low backlash as our testing allows. Look for more new product releases in 2022. Input Drive Size: 3/8" Drive Shape: Square Length: 178 mm Head Type: Fixed Gear Teeth: 72 Teeth Head Thickness: 13.7mm Product Dimension (Refer Line Drawing Image): T Size: 24.5mm D Size: 28mm H Size: 13.7mm L Size: 178mm