The FC1015 from Cleveland Tank is a brass locking diesel fuel cap with a male thread design, for fuel tank necks that take a male-threaded cap rather than the female style used on most of Cleveland Tank’s other caps. It has a 2.125-inch diameter and 12 threads per inch (12 TPI), and it’s both locking — deterring fuel theft and tampering — and vented, so the tank can equalize pressure properly as fuel is drawn down instead of risking vacuum lock. Brass construction gives it more heft and durability than Cleveland Tank’s standard aluminum caps. At 1.0 lb and 2.125 x 2.125 x 2.0 inches, the FC1015 is a direct-fit replacement for diesel fuel systems specifying a 2.125-inch, male 12 TPI locking vented cap.

The FC1003 from Cleveland Tank is a brass locking diesel fuel cap with a male thread design, sized at 4.25 inches in diameter for fuel systems needing this larger fitting. The integrated lock secures the tank against theft and tampering, and two keys ship with every cap so there’s already a spare on hand. It has 8 threads per inch (8 TPI) and is built from brass for extra rigidity and durability over a standard aluminum cap. Non-vented, it’s built for fuel systems that vent through a separate equalizer line. At 1.0 lb and 4.25 x 4.25 x 2.0 inches, the FC1003 is a direct-fit replacement for diesel fuel systems specifying a 4.25-inch, male 8 TPI locking brass cap.