This is the charger for Star Pointer's rechargeable battery.
I have had no problems taking a recently charged unit to the field but sometimes I do multiple nights trips. So I brought a spare USB charger, one stays home with my battery charger and one is packed with my travel kit. Works fine and I always have a backup.
I only bought the laser, I have another tracker and was hoping I can use it to help polar align it. (I would have very much liked the MSM, but cannot justify getting another one, even if my current tracker is heavier.) The laser is really strong. It has an on-off button, which means that you can keep it on without having to keep pressing a button, like for some other lasers. You can point at stars quite precisely, the beam seems to almost touch them.
As I said, I was hoping I can use the laser to help polar align my old tracker, but it does not fit in the polar scope well. However, I put in the polar scope and shot the laser through it and that made it a lot easier to do the rough alignment. It took under one minute. So I assume this procedure will be even easier with MSM. So get the laser, it's a no-brainer.
I recently purchased a second USB charger for my Move Shoot Move star tracker kit so I could keep one in my camera bag and a backup in my car. This enables me to always have a charged battery for my laser pointer. I've been very impressed with the tracker and included items and my Milky Way photos have improved as a result of adding them to my camera bag.