Here are two part numbers for the reservoir tube for current model DWTs and comparators. Some models are P5515, P3111, P3112, P3113, P3114, P3115, P3116, P3123, P3123, P3124, P3125, P3211, P3213, P3214, P3223 and P3224.
Part Number: 3921608
Description: P109304,RESERVOIR TUBE, ACRYLIC
Part Number: 3921726
Description: P109331,RESERVOIR TUBE, ALUMINUM
The reservoir is about 5.5 cm (2.2 in) tall and 7 cm (2.8 in) inside diameter. With internal components (reservoir valve and seat), the usable volume of the reservoir is about 400 cubic centimeters (25 cubic inches), or about 0.4 liters or 13.5 US fluid ounces or 0.4 US quart.
O-ring (Viton is default material but Buna-n is also available)
3865326 (54-703-145),O-RING VITON 2-9/16 X 3/32 XSEC
3864910 (54-700-145),O-RING BUNA N 2-9/16 X 3/32 XSEC
Quotes can be made by emailing Orders Team or calling +1.877.355.3225