Not sure, they arent my videos. Id say likely buckshot. Either 9 pellets of 00/SG which is the same as the US 00 buck load or SSG, standing for special small game, an 18 pellet load. The shot size is about half way between US buck #2 and #3 sizes. There was also a 27 pellet load of AAA size buck which might still be in use. These were all made by our Olin branch of Winchester.
A lot of US shot size ammo comes in as well these days( #1 and 2 buck, #4 buck etc) which was not available previously. I used to have to custom order 1 7/8oz loads BB, 3" loads of 15 pellet 00 buck in 12ga and also the 18 pellet OO buck loads for a 12ga 3.5"chamber and 10 gauge double I used to have. You could get the US sizes through our remington and winchester distributors as long as you ordered by the case load and didnt mind the 6 month wait. With covid that wait is probably now infinity