A luminaire for below-grade use comprises three primary components: 1) a top; 2) a lamp housing; and 3) a bottom. The top comprises a lens and a lens frame, and may include additional components. The lamp housing can be molded in various depths to accommodate various lighting systems, and is frusto-conical...http://www.google.ca/patents/US5908236?utm_source=gb-gplus-sharePatent US5908236 - Modular below-grade luminaire
