im not sure but if i read it correct it tells you the differnce.
The Mongoose Optimum is designed to give you the best of both worlds the "Lifter" and the "Equalizer" has to offer. The Optimum can be used with or without the finger strap, by simply leaving it under the fingers or putting it around them.
the optimum has both the equalizer and the lefter, with the ability to not use finger straps.
not sure if you read that right or not