The site that used to manufacture this tablet has been under construction for 10 years, I am guessing there will be no driver updates. VisTablet VT Penpad uses a WALTOP chipset so if you click the device ID for this tablet there will be other devices that are same and share the drivers.
VisTablet VT 12 USB Driver
File: VT-12-V3-48.zip
e9dbe70984038c3e8c37563e1f3caf7b0c85f749f4e25281cc5b306e76d3eea8
VisTablet VT 12 USB Driver
File: WindowsDriver_VT_B8.zip
63a0a289f35eb0ad359d139b31c175e663ad746434d24019ffc60e7efd8d5e04
VisTablet VT 12 USB Driver
File: MacDriverForVT.zip
e5c7a7fd673b13277f751fd495a51ab74dd3c1c012ea93e326302932e17a7702
Active Area: 10.00 x 6.25" (25.40 x 15.88 cm)
Dimensions: 12.09 x 9.76 x 0.33" (30.70 x 24.80 x 0.85 cm)
Resolution: 4,000 LPI
Report Rate: 250 RPS
Pen Pressure: 2,048 Levels
Reading Height: 0.39" (1.0 cm)
Hot Keys: 4
Function Keys: 16
LED Indication: 1
Power Consumption: 0.35 W
Weight: 20.4 oz (577.0 g)