Flatback nail rhinestones sold in grid boxes: 6-grid and 12-grid cases, and two-packs of 6-grid boxes, in colours such as #06 Rose Red, #15 Blue, #30 Phantom, RB-04 Aurora AB, RB-10 Sapphire and RB-12 Mine Gold. Each listing is a single colour or mix, and stock is tracked listing by listing, so check the colour you need before you plan a design.
Use a thick gel made for holding stones. Apply a small amount of the gel where the stone will sit, place the rhinestone with a wax pencil or pickup tool and press it gently into place, then cure. Add more gel around the edges of larger stones to lock them in, cure again, and keep top coat off the faceted surface so the stone keeps its sparkle.
With the right gel, a clean placement and a full cure, rhinestones and 3D pieces can stay secure for up to 3 to 4 weeks. Most stones come off early because there is not enough gel around the base or because the client catches them, so build a small collar of gel around larger stones and smooth the edges.
The number tells you how many compartments the case has, so a 12-grid case has twice as many sections as a 6-grid case. Each listing names its colour or mix, and some colours come as a two-pack of 6-grid cases. Read the listing for what the case holds before you order, and keep cases closed so stones do not mix.
Lift the stones first: file around their base to break the gel holding them, then ease them off with an orangewood stick, and keep the stones you want to reuse. Then remove the gel underneath the usual way for your system. Do not prise stones off with force, which can damage the natural nail.