Molded tooth chain is the type found on many boat canvas covers. The #10 Slider has the square end tabs. the other widely used slider is a #8 and that one has rounded slider tab ends.
YKK10 216 250 Separating Large Plastic Zippers - UK
Ykk Vislon Slider
Vislon Zipper Pull Slider #10 Metal Locking - Double
Marine Zippers Giving You Trouble?
Zipper Slider, 2 Piece, Boat Canvas #10 YKK Vislon Single Pull Tab
Installing a Zipper Slider or Puller on a Zipper
Zipper Slider, 2 Piece, Boat Canvas #10 YKK Vislon Single Pull Tab
#10 Extra Heavy Molded Pulls for Heavy Duty Molded YKK
YKK10 146 215 Separating Large Plastic Zippers - UK
YKK® #10 Black Style B Double Locking Metal Zipper Pull (Molded
Zipper basics and sewing techniques - Marine Fabricator
Ykk Number 10 - UK