You can use any brand and any flavor of fruit-flavored gelatin. The gelatin must be flavored and sweetened --do not use unsweetened gelatin packets! You can use sugar-free gelatin, which uses sugar replacers instead of granulated sugar. Be aware that the weight of the sugar-free gelatin packages are different (due to the sugar substitute used) so the weights used in the recipe are for standard gelatin, to keep things as simple as possible. I also used standard flavors, with one exception. The regular strawberry and raspberry flavors available all produced a bright pink color—not pastel enough for me—so I used a “natural” strawberry lemonade variety I found, made with natural food coloring. This color was much softer and gave me a nice subtle pink. If you can’t find something similar, your pink color might be brighter than mine. I found the natural flavor at my local Target, and it was made by Jell-O.