Flexible Filament Fingertip for Prosthetic hands

My attempt to create a flexible filament fingertip for the Cyborg Beast prosthetic hand. There are multiple design attempts. The one pictured is the Flexible Filament Fingertip Zip Tie version. Sadly, this failed what I consider to be the big test for a grip solution: holding a glass. Seems the flexible filament is still too slippery. Maybe if it was printed in something like Layfoam? Not sure. The others are previous experiments with the design and for reference.