OWS (Outer Wheel slider) is an excellent upgrade from traditional sail slides to reduce friction when hoisting and dousing the main sail.
The depth and the shape of the slug is designed to correspond to sail slide HA 91 from Holt Allen and A 009 from Bainbridge. The four wheels roll on the aft side of the mast section while the slug slides inside the luff groove. 

511-743-01 will fit mast sections of the following brands/models:

Isomat NG70

Briand/Pettersson 160x120 mm (Maxi 87)

Sparcraft: NG60; NG70; NG80; NG86; F580; F740; F1060; F1395; S1630;
S2100; F2390; F3360; F4600

Z-Spars: Z902; Z1001; Z1250; Z1400

For all technical information - https://support.seldenmast.com/en/products/sail_hardware/ows_sliders.html

To acheive maximum strength, the OWS slider should be attached to the main sail using a webbing strap. All sliders for webbing can be used for headboard attachments and as intermediate sliders.

H: 55 mm
D: 8 mm
E: 21 mm
SWL+Horizontal: 2.50 kN
RM: 75.00 kNm
FitsLuffGroove: 12.00 mm
Z: 5.40 mm
X: 9.80 mm
T: 10.50 mm
Y: 20.70 mm