This 638nm 635nm orange red laser module with built-in driver is an industrial electronic component and used for industrial testament, Lab etc.
This is a high power laser module comes with Aluminum Heasink 29x29x29mm, which can effective remove heat when the laser module is working, it can thus work continuously within10 minutes without additional cooling device, please connect it to 3-5v voltage.
The 638nm Laser has bigger laser beam divergence than normal 650nm 658nm laser, so the 638nm laser dot shape is more than different from  650nm 658nm laser, 638nm laser dot is not so much round, please refer to the pictures below for its real dot shape respectively at 4mm and 2mm.
Please be careful when you doing some test on it if there is no temperature control device. The laser module is and precise and sensitive optical instrument. Before carrying on some laser DIY activities, please read about the technical information first and protect your eyes before laser ray. Be sure the operator has experience in optics DIY or testingg

Package:

1 x New 635nm 638nm 300mw orange red laser module Focusable with Heatsink