HDE 4 in 1 Laser Pointer PDA Stylus LED Light Pen by HDE. $2.50. 100% Brand new 4 in1 red laser pointer, PDA stylus pen, white LED light, black ball pen. Best suitable kit for professors, teachers, doctors, student presentation and etc. Press button for red laser beam or LED light and twist barrel for PDA stylus or ball pen. Red laser with 650nm wavelength. Max Output power: <5mW.