The E locus controls extension of color through the coat. A rabbit can be either E(s)_, E_, e(j)_ or ee.

E(s)_ is responsible for Steel color. In heterozygotes, this causes the typical Steel color. In homozygotes E(s)E(s), aka double Steels or hidden Steels, these rabbits tend to be very dark colored and closely resemble Selfs. E(s) is the most dominant on the E locus. Varieties recognized in Holland Lops that are E(s)_ at the E locus are:
~Black/Blue/Chocolate/Lilac GT/ST Steel

E_ is responsible for full-extension color. E is recessive to E(s) but dominant to e(j) and e. Varieties recognized in Holland Lops that are E_ at the E locus are:
~Black
~Blue
~Chocolate
~Lilac
~Agoutis
~Smoke Pearl
~Seal
~Siamese Sable
~Pointed White
~Black/Blue/Chocolate/Lilac Otter

e(j) is responsible for harlequin/tricolor. Tricolor is the Broken form of Harlequin. e(j) is recessive to E(s) and E but dominant to e. Varieties recognized in Holland Lops that are e(j)_ at the E locus are:
~Black/Blue/Chocolate/Lilac Tricolor

e is responsible for non-extension color. e is recessive to E(s), E, and e(j). Varieties recognized in Holland Lops that are ee at the E locus are:
~Black/Blue/Chocolate/Lilac Tortoise
~Sable Point
~Orange
~Frosty
~Cream
~Red