New to all the terms...I need to buy the trims for my basement and I I came across Halo 301P & Halo 401P. What is the difference?
Do I need the baffle too or I can just put the trim?
The difference is in the size and the light bulb you can (should) use with each. The 301 trim is sized for an R30 bulb, the 401 for an R40 reflector bulb. If you buy the recessed fixture and the trim, you should be all set up.