SSA will be hosting a few night games throughout the session. Airsoft can be a dangerous sport but more so at night where your sight is crippled. To help decrease the amount of accidents we have at these games there will be more rules added on to maintain safety. The main rules is each player must have someway to designate where they are shooting at night.
A tracer unit is the recommended and most tactical way to designate where you are shooting. A good cheap tracer unit would be the echo 1 tracer that is only $60. I personally own it and I haven't had any problems with it yet. Matrix tracer ammo is relatively cheap and they are reliable bbs. Performance hobbies in webster only carries the Madbull kind if you need a local source but those stay lit long too.
Another option you have are lasers and flashlights. These tools only need to be on when you start shooting your weapon otherwise they can be off. the flashlight can be a flashing type too it doesn't need to remain "solid". To be able to use a laser it must have a visible beam night I own a green laser and at night it has a very distinguished beam to track