They're anderson connectors, right? But they look to be moulded. As in I can't change the wires. They were from a largeish (8kva) ups unit that was scrapped.
Do look like Anderson connectors. Usually can remove the wire out of them with a flat head screwdriver and there is a tab inside. They are about £12 per pair usually and handy for jump start points. (Aa and rac used to have them on the front bumpers etc)
If they're real Andersons, you need to pull up on the "leaf spring" at the open end and the contacts will slide out - a scriber/similar should get under them. They're useful, I have 'em interrupting jump leads / charger cables so I can clamp onto the batteries with no worries about shorting out, then hook the two Andersons together. Dave H. (the other one)
Ive had a better look. They are an APC copy of Anderson connectors. From youtube the design and internals look identical but the plastic bit is a little different shape. I took them apart just like you would Anderson units. The terminals have been crimped to the wires, so they may be useful but im not sure - it depends if i want to join wires, or if i can think up a setup where the wires are long enough. Ill probably step over them for a couple of years and then get irritated and throw them out! Thanks for telling me how to get them apart!
You can get new terminals: https://www.altecautomotive.co.uk/anderson-power-connector-terminals--pair-438-p.asp They look like the smaller connectors they do so they're only £3 or so new.
