Kaydon Reali-Slim Duplex Bearings MATCHED PAIR KD040BR7N READ 4 x 5 x .5 ABEC 7

Description

These have been handled appropriately.  Auction is for one matched pair.  I have 2 pairs of these bearings.
These are already nicely discounted from new.  But, don't be shy, if you are okay with the risk of someone else getting these . . . make an offer.  Depends on the day, I might just take it.
Manufacturers code (?) Printed on bearings:  32828
Part number with Kaydon descriptions per link below pasted into your brower for verification.
K – AISI 52100 Steel No seals or shields
D - 1⁄2" x 1⁄2" (.500 x .500)
040 = 4.0" Bore
B - Angular contact pair—duplexed back to back
R - Standard one-piece formed ring with circular pockets - A
7?
Position 8 – Precision (ABEC Specifications are per ABMA Standard 26.2)
0 Kaydon Precision Class 1 per ABEC 1F
1 Kaydon Precision Class 1 with Class 4 Runouts
2 Kaydon Precision Class 1 with Class 6 Runouts
3 Kaydon Precision Class 3 per ABEC 3F
4 Kaydon Precision Class
4 per ABEC
5F
6 Kaydon Precision Class 6 per ABEC 7F
8 Other
My guess is that it is ABEC 7
N .0005" to .0015" Preload
The image on the far left is back to back.
Duplexed bearings
Type A bearings are furnished as matched sets—available direct from the factory—when they are to be mounted adjacently or with equal length inner and outer race spacers. Duplexed bearings are supplied in back-to-back, face-to-face, or tandem arrangements. Sets of three, four or more bearings can also be matched where conditions require additional capacity and there is insufficient space radially for larger bearings. I have 2 pair, packaged separately.  Possibly a set of 4?
The bearings in these sets are matched within close limits for size of bore and outside diameter. Each set is marked with a 'V' across the bores and outside diameters
at the high point of radial runout to indicate the proper orientation
of the races at installation.
A
back-to-back arrangement
offers greater rigidity under moment loading and should be used when the space between single bearings is small or when a single pair of adjacent bearings is employed.
Copy and paste the link below to see where I derived the specifications of this listing, for your convenience.  ;o)
kaydonbearings.com/downloads/catalog300/Kaydon_300_PartNumberIDs.pdf