The Yonico 12202 rail and stile conversion kit to replaces the existing Groove cutters on your Yonico rail & stile router bit set. Standard rail & stile router bits create 1/4" Grooves for the center panel. When using 1/4" Plywood for the panel, 1/4" Grooves will be too large as 1/4" Plywood is finished down to slightly less than 1/4". This conversion kit allows 1/4" Plywood (actual 5.5mm) to be used as center panels for rail & stile doors. (For 5.2mm plywood use Yonico 12201 rail & stile conversion kit.) Note: This kit contains the 2 blades only. The rail and stile bits must be purchased separately. This set is compatible only with: • Yonico 12241 • Yonico 12243 • Yonico 12243Q • Yonico 12249 • Yonico 12335 • Yonico 12336 • Yonico 12338 • Yonico 12343 • Yonico 12345 • Yonico 12350 • Yonico 12432 • Yonico 12536.