I get my cheap ones from eBay. Lots of choices there so no need to link anything. By appearance they all look about the same to me. I use these as passive ADS, and other various stuff. The quality varies a lot from sleeve to sleeve, as does the firmness. Some last months and others tear after a few uses. Totally expected as they are cheap Chinese products. But the cost is low enough that I price wastage into the order.
I’m not sure what you count as hard sleeves, so perhaps these fall into that category, but get my higher quality ones from Total Man Shop. If you a 10 pack its $95 US, which is a lot per sleeve, but I cut them in half for use with my vacuum cup, so its actually 20, and these last a lot longer (I’ve been using the one I have on now for almost 4 months, and I put some lotion on before using them that is rumored to degrade the silicone over time but this one is ‘hanging’ tough), have consistent quality and good customer service. I actually had one fail after 3 or 4 uses and when I emailed them about it they sent me 2 new sleeves for no charge. Also over a certain amount on your order then I think they waive the shipping. These are the ones I use for hanging and tension ADS and are the best I’ve encountered.
