These "tin based" silicone molds are great for quick last minute appliances. You can run Bondo, Gellatin, 3rd Degree, and/or Skin Tite through them for any quick effect these molds offer. Very small and compact, so they make great for an addition to your kit. These appliance sets are approximately the size of an eyelash case.
Caution: You may run latex in these molds, but once latex is ran through these molds, you will not be able to run silicone through them. When latex comes in contact with these silicone molds, they don't allow any silicone to set anymore. So choose either silicone or latex when using these molds. If you work with both silicone and latex, you can always have one of each mold for latex, and one of each mold for silicone.