Features: 1. High-Power Blue Driver Circuit, In The Previous Version Of The Increase Of 5521DC Direct Port, To Solve The Market On The Stage Laser Driver Can Not Be Directly Connected To The Defects Of The Power Supply. 2. This Is Not Only For Laser Drive, But Also Can Be Used For All Kinds Of Buck Constant Current Source, Most Of The Market Does Not Come With Reverse Protection And Fan Input Port, And Increased Precision Light Source. 3. And Add A Precision Light Source Required To Protect The Device Slow Start 30 Seconds, Which Greatly Improves The Convenience Of Non-Professional Users, And The Use Of More Convenient, Easy To Use, The Fan Input Port, The Power Supply Can Be Used For All Kinds Of Constant Current Source. 4. More Convenient, More Simple To Use. 5. TTL Modulation Instructions: External 0-5v Voltage Signal (0 Is Off, 5 Is On, The Frequency Determines The Speed Of The Laser Light Flashes), If You Just Do Long Bright Laser Light Source This Function Can Be Ignored. Description: 1. Circuit Control: 12V Step-Down Circuit, Constant Current Output (Both Current And Voltage Are Adjustable) 2. Output Specification: Max 3a 3. Scope Of Application: 200mW-3W 405/445/520nm Red, Green And Blue Laser Drive Power 4. Input Voltage: 8-14V NOTE: Different batches may have differences in product appearance, color, and printed characters, which will not affect the use size: 29 x 49mm (WidthxLength), Component Height Including Board 14.5mm Material: PCB colour: green Package Contents: 1 x Step Down Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.