It's a 410 Shotgun shell, much more accurate than a pistol cartridge.  

Be prepared to pay $75 to an electrician to flip a tripped breaker or change a ceiling light bulb, $75 to a plumber to change a flapper in a toilet or a cartridge in a faucet, $750 to replace a hot water tank, fridge, washer/dryer, $100 to a cable/internet tech to unplug and plug in a modem, the list goes on.

@Adam DrummondAdam, your profile tells me you've been in the business for a bit, but still, word to the wise -- respirator with organic vapor cartridges is a must when working with oil-based poly.

Pay roughly the same and have 3 ductless split systems installed in the house with one main unit and 2 cartridges (1 for each bedroom)3.

Please make sure you or workers wear cartridge style air respirator when removing that carpet and spraying with any of these strong chemicals also probably should wear a white tyvek style suit etc. 

I am sure his security deposit will be used up on junk and trash removal, cleaning, fixing everything he broke.2) Among the things he left behind were a huge nitrous oxide tank in the bedroom closet and six boxes totaling literally thousands of steel cartridges that say "ultra pure" on them. 

If that red wall is redgard coating, and you're going to tile it, I'd say before you do that go all in: open the wall, and replace the whole valve with a modern one where the cartridge is easily replaceable.

I’ll do you one better even - I have made my own before using a $40 pentek 20” filter housing and buying the cartridge for $79 from aquios.

I remember when people would buy the printers with the free cartridge because it was cheaper than buying a replacement ink cartridge!

Most are value engineered to hit a price point with cheaper plastic parts, valves, cartridges.