#4-40x1/2in Yellow Zinc Standoff, M/M, 1/4in threaded ends $0.50 #4-40 x 1/2" yellow zinc coated (chromate) steel standoff. IR Reflector sensor with leads $1.00 Reflective optical sensor with transistor output. 44mm Piezo Speaker $2.25 For making a LOUD beep, this piezo suits your need. Comes mounted in a plastic case with mounting tabs. Maxell LR44 […]