Basic product to ask semi permanent polish brush, a polymerize under UV lamp. Use very little product and especially the free edge border to ensure the holding. (See videos on the net). Easy to use if one has a little training and care has put ordinary varnish. Buy good on a uv lamp. I polymerizes 4 minutes instead of 2 recommended on basis of experience shared with a colleague. My experience: perfect outfit two weeks. After I no longer found it to be perfect (fast regrowth of my nails). The nails covered these 4 solid layers s very little spoil and break less.