Check the listing for details. Razor mx 350 mx400 Variable Speed Kit 24V throttle and controller, 24volt Kit. Condition: New. Listed at 47.99 USD. Fast Scooters does it again with our Variable Speed Kit AND Fancy 4 led Throttle With Key! If you want any other throttle pictured you must send a message with the # in pic at checkout and "ad" the note after you type it or it wont be sent. We will send the # you request. Reads battery voltage Variable speed means giving your scooter the ability to control the speed from slow to fast and everything in between compared to stock style full throttle and off is a must have.. This kit also has optional Brake Light and Taillight or Headlight outputs to make your Razor E200 and 300 a 1 of a kind and much safer! We were the original inventors of the variable speed kits and they are such a hit we offer the digital version for people wanting exact voltage left in the batteries. This kit now works with all E200,E300,E325S and mx 350, 400, rsf and rx200. If you would taillights,brake lights or a headlight check our ebay store for optional ad ons for this kit including mountable speed reducers to limit top speed to keep kids safe..