"Looks like a 5mm LED & has a clear transparent lens.Specifications:- NPN Collector-to-Emmiter Breakdown voltage: 30V- Emitter-to-Collector Breakdown voltage: 5V- Collector-to-Emmiter Saturation voltage: 0.8V Max- Collector Dark current: 100nA@10V(Vce)- Rise and Fall time: 3uS @ 5V(Vce)- Breakdown voltage: 5V- Power Dissipation: 100mW max- Collector: Short Leg - Emitter: Long Leg "