We evaluated a polyethylene bulb reservoir fabricated at the Pocatello Supply Depot, Pocatello, Idaho, as a potential cost savings replacement for the McBride rubber device that is used as a tranquilizer trap device (TTD). The polyethylene devices, also called pipette TTDs, were formulated with 0.6 g of propiopromazine hydrochloride (PPZH) and 0.4 g of ascorbic acid, an antioxidant. The pipette bulb was secured to a 1.6 mm-diameter cable and the cable was attached to the trap jaw. TTD testing was conducted during routine operational control under an Investigational New Animal Drug application (INAD 9528) from the U.S. Food and Drug Administration. The targeted animals were feral dogs in Guam, coyotes in Utah and Idaho, and gray wolves in Minnesota. Various degrees of tranquilization, ranging from quietness and lack of attention to sleepiness, were observed in the animals. Percent of tranquilization effects observed in feral dogs, coyotes, and wolves were 67%, 90%, and 67%, respectively. Evidence of reduced struggling and reduced injuries to feet and legs was observed. Tranquilization effects were also observed in non-target animals such as badgers, skunks, and raccoons. A mortality that was probably related to heat stress was recorded in one juvenile wolf. A major drawback of the pipette TTD was leakage at the stem attached to the trap jaw. Degradation of PPZH was also observed but was reduced compared to formulations without ascorbic acid.