An alternate base and a pair of alternate holders for junnno's excellent universal arm mount holder. Use with arms, nuts, and bolts from the original thing. pennybase is narrow enough to fit on my Printrbot Simple XL bed. It also has "ballast trays" for $2 of pennies to ensure it sits securely. holder-a adds a charging cable hole in the center of the tray and has some random cutouts to reduce material. holder-b-phone is similar, but has a slight indentation to keep an iPhone 5c (or similar sized device) centered in portrait orientation. Intended to be printed on its side. See http://www.thingiverse.com/make:148356 for print details and a few more photos.