Each combo pairs one gel and lacquer duo with the base and top gel of its line. DND classic combos add Base #500 and Top #600 No Cleanse, DC combos add Base #800 and Top #900 No Cleanse, and DIVA combos ship as four bottles: DIVA Base #100, DIVA Top #300 No Cleanse, the gel colour and its matching lacquer. The shade number is in the title.
Prep the nail, apply a thin layer of the base and cure it, 30 seconds under LED or 2 minutes under UV. Apply a thin coat of colour, cap the free edge and cure it, 30 to 60 seconds under LED or about 2 minutes under UV, then repeat with a second thin coat. Seal with the no-cleanse top gel and cure fully; there is no sticky layer to wipe.
Yes. DND, DC and DIVA base and top gels are cross-compatible, so a DC base works under a classic DND colour and the other way round. Matching the base and top to the colour line still gives the most predictable wear. DC colour should always go on over a base coat, because DC needs a base for adhesion.
With correct prep, thin coats and the full base, colour and top system, DND gel lasts up to three weeks. To remove it, file the top layer to break the seal, soak in 100% acetone for about 10 to 15 minutes and lift the softened gel with an orangewood stick without scraping. The lacquer in the duo comes off with regular remover.
Not necessarily. Many combos are priced at about the sum of the duo and the base and top pair, so the main benefit is convenience: one listing gives a complete starter set for one shade. Compare the combo price with the single duo and the base and top combo on their own listings before you order.