Modular stackable light diffusers

A diffuser for use in a modular light fixture comprising:

• an outer shell having a length;
• an internal bore extending through the outer shell and defining an opening at a first end and a second end of the outer shell;
• a first connector disposed at the first end;
• a second connector disposed at the second end, the second connector comprising an internal threaded portion that extends along at least a quarter of the length of the outer shell;
• and
• one or more fins extending radially from an outer surface of the outer shell,
• wherein:
• the one or more fins selectively engage notches within the modular light fixture, such that a first shade of the modular light fixture and a second shade of the modular light fixture cannot rotate relative to each other.

A collar and diffuser assembly for use in modular light fixtures comprising:

• a collar comprising:
• a body having an upper surface and a lower surface,
• one or more walls extending from the lower surface of the body,
• one or more apertures extending through the body, and
• a connection element;
• and
• a diffuser comprising:
• an outer shell extending along a longitudinal axis, and
• a connector configured to engage the connection element of the collar;
• wherein:
• the connection element of the collar engages the connector of the diffuser and resists axial separation while allowing rotational movement of the diffuser relative to the collar.