The same disk magnets are used in parts of the following products:
Vernier Dynamics System (VDS, discontinued)
Dynamics Cart and Track System (DTS)
Dynamics Cart and Track System (DTS-LONG)
Dynamics Cart and Track System with Go Direct® Sensor Carts (DTS-GDX)
Dynamics Cart and Track System with Go Direct® Sensor Carts (DTS-GDX-LONG)
Dynamics Cart and Track System with Motion Encoder (DTS-EC)
Dynamics Cart and Track System with Motion Encoder (DTS-EC-LONG)
Dynamics Cart Replacement Tabs (DTS-TABS)
Eddy Current Brake (DTS-ECB)
Go Direct® Sensor Cart Accessory Kit (GDX-CART-AK)
Adjustable End Stop (AS-VDS)

Specifications

Dimensions Diameter 0.5 in
Thickness 0.25 in
Grade N35
Theoretical flux density at surface 4278 G

The manufacturer supplies the following information:

Related:
How are magnets installed in the Adjustable End Stops?