Here's a link to the various board types -
http://www.fotosidan.se/forum/showthread.php?t=15567
And here's the info from that thread:
All of the current lens panels are approximately 80 mm in outer diameter. Some are metal and some are plastic. Both can be used interchangeably. Recommended focal lengths can change somewhat from one enlarger to another due to the available length of bellows, but in general the
numbers given below will be true.
Siriopla 39 = plastic, relatively flat w/ 39mm threaded lens mount, usually used with 50-90mm lenses (essentially the same thing in metal is Lapla 39)
Siriotub 39 = plastic, recessed lens panel (recessed about 15mm), w/ 39mm threaded lens mount, for short lenses usually 35-50mm (same thing in metal is Setopla 2839)
Vegatub 39 = plastic, w/ 39mm threaded lens mount, extended lens panel (40mm extension) generally used for 100-105mm lenses. Includes a red filter on an extension arm so the filter can swing under the mounted lens. (Normal red
filters would not be able to fit in front of the lens with their short mounting shafts.)
Flaring = plastic lens mount adapter to fit 25mm threaded lenses into 39mm threaded lens panels.
Neriotub = plastic recessed lens panel approximately 40mm recessed) w/ 39mm threaded lens mount, for use with 28-35mm enlarging lenses. Metal equivalent is Seipla.
Lapla 39, Lapla 42 Lapla 50 = metal, flat lens panel threaded as indicated by the number. Generally used with 80-150mm lenses. Plastic equivalent is Siriopla 39.
Setopla 2839 = metal, recessed (approx. 17mm) lens panel, w/ 39mm threaded lens mount, generally used with 35-50mm lenses. Plastic equivalent is Siriotub 39.
Seipla 7539 = metal recesses (approx. 33mm) lens panel, w/ 39mm threaded lens
mount, generally used with 28mm enlarging lenses. Plastic equivalent is
Neriotub.
Femotub = metal extension tubes for use with any of the above lens panels, to extend the bellows for closer focusing, when making reductions. It attaches to the lens stage of the enlarger, and then you attach the lens panel to the Femotub.
Roding 50 = metal extended lens panel for use with 135 - 150mm lenses with 50mm lens thread.