Plumbing content - help me figure out which valve to get

The water heater started dripping over the weekend. It's in the attic, and I have a tray, and the tray is doing its job. I actually discovered the leak because the tray runoff pipe outside was trickling water.

We shut the water off at the water heater cutoff.

I ran the hot water until I gave up. It never slowed down.

I went back to the valve, and after a surprisingly small amount of pressure, the handle popped right off. It's stuck on. I need to get a replacement ASAP. 

I've googled the model number on the handle, and there are actually a series of SKUs.

I see BRS, NPT, GWP, FIP, FPT, MHT. I have no idea. I figured you lot might be able to make sense out of this. I'm finding it a bit opaque.

Photos:

I found a scrap bit of pipe lying next to the unit, so if this helps...

Finally, is this a plausible replacement?

https://www.homedepot.com/p/Everbilt-3-4-in-Lead-Free-Brass-Threaded-FPT-x-FPT-Ball-Valve-116-2-34-EB/205816051

Yes it'll work fine.

You have a 3/4" ball valve with NPTF connections

BRS brass

NPT National Pipe Thread - these are tapered so they seal nicely but use some teflon tape.

GWP, FIP, FPT, MHT - no clue, however whatever you fine at the Big Orange or Blowe's that's a brass 3/4" NPTF ball valve will work fine.

FPT Female Pipe Thread?

The 600 under 3/4 means for 600 pound service - often more of a pattern type than pressure rating.

In reply to akamcfly :

That's awesome, and very greatly appreciated! Thank you!

This story is an example of why a guy should cycle those valves every so often.

And no, I haven't done any of mine for way too long.