The SCCA is usually very strict in this area, if your safety equipment doesn’t meet requirements, you most likely won’t be allowed to race, or at most be allowed to run only one event.
The fire system consists of a bottle in the left side pod, lines running to the engine and driver compartment, and a pull handle mounted in the driver’s compartment.
The original bottle is a small (5 lb?) steel bottle, with no gauge. The bottle is weighed to determine how full it is. This could cause you to be asked to remove the bottle when having the car teched (and you should probably do it yourself, anyway).
Lines should run behind dash and between the engine and firewall. Check for crimping and loose fittings.
“Standard” belts are 3 inches wide. Lap belts can now be 2 inches wide. Shoulder belts can be two inches wide only if you are using a HANS device.
There are a wide variety of brands and prices.
SFI and FIA belts have different validity and labeling standards.
Age and the elements may make the expiration / manufacture date illegible over time. If that happens, the car will probably fail tech.