Indoor Chrono

I use a Competition Electronics Prochrono with LED light strips from Home Depot attached to the light diffuser panels. Works great.
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I have owned just about every model ever made at one time or another. I would stay away from the Chrony models , not that they don’t work they are just a pain to set up. Currently I use the Caldwell G2 which has lights built in and I also have a lab radar . If you are looking for a simple inexpensive one see if you can find a combro it attaches to the barrel and you can get a reading after every shot they are sometimes hard to find but they only cost around $50 I use one when I’m traveling light as it’s pretty small

here is a link but it’s not in stock check it out on YouTube 

https://www.amazon.co.uk/Combro-Chronograph-Chronoscope-Shooting-Chrono/dp/B0728HHJ36
 
I have a Combro Chronoscope and it works fine. I also have one of those cheap Chinese ones that also fixes to the end of the barrel. It works just as well and matches the Combro velocities. I think that I paid about 30 bucks for it. It is USB rechargeable and has infrared sensors and will work in the dark. The cons are, it reads in metric only and the instructions are in Chinese. They both work as well indoors as out but the Comro, like others, doesn't like fluorescent lighting.