McMaster-Carr has some nice small 12v plastic ones--not cheap at US$42, but they work very well; we use them to inject dye into water for visualization; search part no. 7876K11
McMaster-Carr has some nice small 12v plastic ones--not cheap at US$42, but they work very well; we use them to inject dye into water for visualization; search part no. 7876K11