AstroSystems - 2.00 inch Secondary Holder - 1/4 inch shaft with 3/8 inch adapter

AstroSystems is the largest supplier of secondary holders and spiders to the astronomical community.   There are no tools needed
to adjust holders of 2.6 inches or larger in minor axis size; they come standard with thumbscrews.  Holders from 2.1 inches and
smaller are supplied with a hex key that gives positive seating in the hex screw even in the dark.  All sizes feature our
innovative four screw/two-axis adjustment that greatly simplifies collimation.   With a four screw adjustment, each screw is
centered between the spider vanes, making collimation adjustments a snap.  Two nuts with nylon washers position the holder
laterally and also allow easy adjustment of the rotation.  The secondary mirror is held securely yet safely against the front lip
of the aluminum bezel with polyester batting.  Available in 19 sizes, ranging from 1.3 inch to 7.0 inch.  Use the link below for
dimensions, exact weight and sizing. 

These have a 1/4" mounting stud and a 1/4" to 3/8" bushing to fit both 1/4" and 3/8" spiders.  The smaller diameter mounting stud
reduces the weight by 50%.  They utilize set screws for adjustment and the proper size hex key is supplied.