ASA rules.
Before the game, one of the players from team X asks what bats are they allowed to use. I say "ASA approved bats". He says The "Freak and Freak Plus" and I say "As long as they are stamped". I'm brand new to umpiring and I didn't have my non-approved bats list with me

(they called me last minute to umpire 2 games). The catcher said to me, "Not the Freak +, make sure to keep and eye out for that for me would ya?" I say "okay"... Well I didn't keep an eye out for the bat (which is a USSSA bat) and team X used the bat a lot in the game. Well it comes down to the 7th inning and team X ties it up in the top of the inning. Then the home team scores 0 in the bottom... To make a long story short, the game went into 9 innings and team x goes on a 14 run scoring tear (not using an illegal bat). When team A comes into the dugout after making 3 outs one of the guys says "Can we appeal that the other team used an illegal bat?" I say no, you have to appeal that when it's being used. And another guy says "He told you to watch for that bat?" I say "Sorry, I didn't see the bat" "If you want to appeal a player using an illegal bat you have to do so at the proper time, it's not my responsibilty to stop play and tell the batter to use another bat".. Oh yeah I did tell team X to put the bat away after 7 innings becuase the catcher had brought it to my attention.
I know I probably screwed this up, but I want to learn from it, so I don't make the same mistake again. Team A was okay with everything after the game, and all was good. They were just a little irritated that the other team had just got about 17 hits.