TNK-501 is a single 5.25" bay reservoir. Machined from a solid piece of acetal for maximum reliability, it has a thick acrylic window, front aluminum bezel, and stainless steel top cover. TNK-501 features 8 total G 1/4 BSP threaded sockets: 2 on top, 2 on bottom, and 4 on the back. 6 socket plugs are included.

There are four pre-drilled holes for optional 3mm LEDs on both sides of the acrylic window. Reservoir capacity = approx. 13.3 fl oz (394ml). Weight = 1.5 lbs (0.7kg). Total dimensions = 5.8" (14.8cm) W x 5.4" (13.6cm) L x 1.7" (4.2cm) H.