"Every" KT controller doesn't use those; whcih is a good thing since they're pretty crappy connectors (though by far not the worst).

****
It depends on where it comes from, and what that company had installed on the batch they bought (or what they change them to themselves). IIRC, Conhismotor puts XTs on theirs. I've seen Anderson PP45s on an ad on ebay before.
They look like "standard" automotive bullets. I don't know which diameter they used on that specific controller, but you can get kits of many sizes to create your own adapter, such as these random examples:
https://www.amazon.com/PONFY-Connectors-Terminals-Waterproof-Automotive/dp/B08LPZM5X9/ref=sr_1_3?crid=6NJ44BW90WDG
https://www.amazon.com/Qibaok-Ratcheting-0-5-1-5mm%C2%B2-Connectors-Terminals/dp/B07RZSSTSJ/ref=sr_1_20?crid=6NJ44BW90WDG
If you go that far, you're better off getting the stuff to just put the right connectors on to directly mate to your battery, or change the connectors on *both* to an easy-to-install type that suits your application and current draw needs (minimum of 20-30A, because you should always use connectors/etc that are rated much higher than you need, to ensure they won't degrade or fail from normal usage.
I don't know where you could order a premade adapter from the bullets to your existing battery connectors, other than whatever places custom-make wiring harnesses, adapters, etc., for RC stuff and the like, though there are probably people here on ES that have the tools and parts to do it if you put a want-ad in the items wanted section.
**** They're alright for low-current, but they don't really have significant "springiness" and are often just thin tinplated copper, or other soft metals, so they deform easily and may not fit well together, leaving little surface area in contact and so making the connection higher resistance than it should be. Or worse, not staying plugged in and disconnecting partially from vibration, causing arcing and excessive heating and the potential for fire. While none of these things is all that common a problem, they do happen, and can be prevented by avoiding using them.
Coach said:
Hello all,
First time E-bike builder. Retired EE.
I have a GREAT donor bike and I'm pulling together components for an easy cruiser, centered around a Bafang/Jump front wheel hub motor - 36v 250w.
Just received the KT controller 36v, 15a (KT36/48SVPR-ffF10L) with waterproof plugs. The oddballs are the power plugs, green shrinkwrap on a red, male plug and a black, female plug. Here's a listing w/photos:
https://www.amazon.com/dp/B09MLG5K1D?psc=1&ref=ppx_yo2ov_dt_b_product_details
Does anyone know if these are a standard 3mm, 3.5mm or 4mm?
I'd like to order an adapter instead of making ONE.
Thanks in advance!