2 pack of square style arca compatible quick release plates, similar to the peak design squares. Compatible with things that expect a 38mm arca swiss quick release and peak design's square plate mount on a strap stuff.
Just got one of these included with my Neewer GM41 ball head, which I'm very impressed with indeed for $49.49 with the 25% off coupon here -
https://www.amazon.com.au/dp/B0D9QKBQ64
and found these on a discount deal for a 2 pack, with further -5% for $40 spend on compatible items, which to me made it worth buying a couple for my flash bracket and big 180mm so I don't need to screw and unscrew stuff constantly. The build quality on these seems very good for the money.
Can they be mounted with straps on?