360Q

A luminaire produced by Altman since 1974 and likely the most popular ERS ever.
360Q-ellipsoidal.jpg
http://altmanltg.com/ellipsoidal-360Q-lighting.htm

Available in five different beamspreads:
Lenses (Beam/Field)
4.5 x 6.5 (55°/22°)
6 x 9 (37°/16°)
6 x 12 (26°/11°)
6 x 16 (19°/8.5°)
6 x 22 (11°/8°)

PROs:
Cost. New, approximately 2/3 that of the ETC Source Four, and very inexpensive on the used market.
A simple design that has had minor improvements over the years
Durable, easy to maintain

CONs:
No dichroic reflector, high gate temperature unkind to shutters and gobos
No rotating barrel, some shutter angles impossible to achieve
No interchangeable lens tubes
Not rated for over 750W, although many users put 1000W FEL lamps in them, which can lead to premature socket, shutter and lens failure.
No drop-in iris or accessory slot