As the gym I attend didn't seem to have these I needed to buy some. Where else to look but Decathlon - just the ticket, and available in a range of weights.
There was a choice of weights but the one I bought (1kg) was exactly right for me. The only reason I put 4 stars is because the height of each weight is a bit higher than I anticipated when I was buying online. I could have returned them but I haven't because apart from the height thing they are exactly what I wanted. The reason I bought them is because my cousin had some (different make) and I thought it would be more like those. I would give 4.9 stars but not a full 5 stars if I could.