PN#BBS-10211H SKU#19228 Type: Automatic. SPLN: 1.5″-28. ARM: 5.5″. Worm and Worm Gears: Forged SAE 4140 material. Heat treated to HRC 44-48. Clevis: Forged SAE 1045 material. Machined to OE tolerances. Heat treatment-normalizing. Clevis Pins: SAE 1045 material. Heat treated to HRC 40-48. Pall and Actuator Sleeves: SAE 4140. Heat treated to HRC 45-48.