Major Brands LM317LZ Standard Regulator, 1.2 Volt to 37 Volt, 0.1 Amp, 3 Pin, 5.2 mm H x 5.2 mm L (Pack of 15): Amazon.com: Industrial & Scientific
Amazon.com: LM317 Adjustable Voltage Regulator Board, Digital Display Power Supply Module, Double-Sided Circuit Heat Sink DC 3-30V/ AC 3-20V : Electronics
Amazon.co.jp: CHUI-CC 3D Printer Variable Voltage Regulator High Efficiency Module with Buck Power Supply LM317 Accessory Base : Industrial & Scientific