The Nikon# 85958 Phase Ring is for the 20x Objective with 0.2 N.A. Condenser, part of the Nikon TMS Inverted Microscope system for phase contrast.

The phase ring has the proper pattern on a clear disk that is inserted in the phase slider.

IDENTIFY YOUR MICROSCOPE:  There are several unique phase rings for this microscope, EACH PHASE RING SPECIFIC TO THE CONDENSER AND OBJECTIVES ON YOUR MICROSCOPE.  The microscope condenser is either labeled 0.2 N.A. or 0.3 N.A. as written on the condenser.  Not material to selection of the phase rings, there should be a slider inserted in the condenser that is either pre-centered or with centering adjustments on the edges.  If not, please search our website for the related part.

Which condenser do you have?  The ELWD condenser has an extra-long working distance of 78.2mm and an N.A. of 0.2.  The LWD condenser has a long working distance of 51.0mm and an N.A of 0.3.  The ELWD is suitable for lenses up to 20X, while the LWD can be used with lenses up to 40x.

The 0.2 N.A. condenser (ELWD) accepts a Ph L, Ph1 and Ph2 slider insert (or phase ring) corresponding to the 4x, 10x and 20x phase objectives, respectively.  Note: the 4x phase objective is rare.

The 0.3 N.A. condenser (LWD) accepts a Ph1, Ph2 and Ph3 slider insert corresponding to the 10x, 20x and 40x objectives, respectively.

PLEASE NOTE:  Price is per phase ring.  Each phase ring is manufactured and tested in our shop to meet the specifications of the Nikon original equipment.  Please feel free to email with any questions.