This icons you can resize x2, x3 and more from 32x32 px and they will be stay clear boundary. Because they created by 32x32 pixel grid.
ZIP file included 15 vector icons in SVG format and PNG thumbnails ( 512 x 512 px ). By default SVG files have a 128 px resolution. But if you want you can change it in 2, 3 and more times.