The item is a LM2596 AC DC Buck converter step down module power supply. Priced at 5 for $15. Input voltage 2.5-27VAC or 3-40 VDC, 3 amp max. Output adjustable, 1.5-27VDC, 3 amp max. INput voltage must be at least 2 volts higher than desired output. Size 54mm x 24mm.