Base Gel
Base is either clear or colored, meant to be applied on short to medium nails, flexible and will bend with the nail so recommended to use on short nails or strong mid length because if mid length nails are weak and thin base is too soft and nails will crack and break because base will not keep them from bending. Can be applied directly on clean prepped natural nails.
Builder Gel
Builder Gel is a glue-like gel, it’s a hard form of gel, meant for mid length-long nails. Doesn’t bend at all and will keep natural nails from bending so can be used to strengthen natural nails, they will last longer than the Base Gel. Also can be used to extend nails. Needs a layer of base gel first because it will not stick to natural nail on its own.
Acrygel
Acrygel/Polygel/Acrylatic is a very thick and strong mixture of gel and acrylic. It’s like playdo, very thick and will stay the way you place it - will not leak or lose its shape. Mostly used for extending nails and repairing cracked or broken nails, can also be used to repair uneven nails because of its thick consistency, also needs a layer of base underneath to stick to the nails.