It looks like a powder coated cast aluminium coping saw that's been adapted to use a wire (instead of a blade).
Can you provide a link to the video - it looks like there's a brand on the tool - being able to read that would help find you either the tool, or one similar.
The photo is a screenshot from one of Etsuko Watanabe’s YouTube videos. She uses this saw in pretty much every one I’ve seen and it seems to work well. Here’s one of her videos. ...[/USER]
Thanks - I can see in the video that the brand is "Cafe de Savon"
On the website @aksamitka
mentioned, it is item number "f3090601"
Now that I can look at the advertisement, yes, it states that it is die-cast aluminum.
I like the wheel adjuster for wire tightness - that's a nice touch.
Cheap price - I wouldn't mind hearing how much it costs you for shipping
The pin-end wires are a consumable (so buy a couple of spares if it doesn't ship with them new).
(Or you could make your wires by creating the end pieces - drill a small hole in a two pieces of size matched small round bar, and insert your own stainless steel wire into the hole and wind it on a little, over itself, to hold when taunt.)
(Alternatively, coping saws are fairly straightforward to modify to hold a wire; some even come pre-set for wires - look for diamond wire scroll/coping saws