The tower also was found to have been assembled correctly according to plans, which called for precast concrete pillars strengthened by seven compression rings
and post-tensioning anchors.
The unit also accepts most 1%-inch eyepieces seated in helical focusers, with non-marring brass compression rings
in collet-style locking mechanisms.
The wide, shallow pistons have two compression rings
instead of the GP6's single ring, but are identical in every other respect.
A typical piston "ring pack" consists of two compression rings
and an oil control ring.
This engine's connecting rods, wrist pins, compression rings
and balance shafts were also used.
The ends of the structure are contained within compression rings
The Perfect Circle Division worked in synchronized teams consisting of engineers from Dana and DaimlerChrysler in Brazil, Germany, and the United States to design a complete set of rings including the upper and intermediate compression rings
, the oil ring expander, the side rail oil ring, and piston rings.
Encore has packaged four compression rings
and an applicator, marketing the combination as the ImpoAid.
Each version comes with both 2- and 1 1/2-inch eyepiece adapters that have non-marring compression rings
. A model having 3 inches of clear aperture (SVF30 for $399) is also available for use with the larger Stellarvue photographic field flatteners.
The engines use oil-cooled three-ring pistons with two compression rings
and an oil scraper ring.
The Astro-Tech one-piece machined 2-inch diagonal uses non-marring compression rings
to hold your eyepieces securely in both the 2-inch eyepiece holder and in the included 2-to-1 1/4-inch eyepiece adapter as well.