Mediterranean No.4 Tile Crafting Stencil Washable Reusable Mylar 10cm or 15cm

The 10cm stencil will fit onto a 4" tile, and the 15cm will fit a 6" tile. Hold or masking tape the stencil in place, then spray or daub paint on with an almost dry brush, building up layers. You can also use a low tack repositioning adhesive with these, then wash it off when done, so you can use the stencils for other crafting.

eBay