This 90mm frame has 2-hole motor mounts and narrow 2.34mm arms, the frame is 2mm thick, and it weighs 3.2gm. This frame was basically designed to make the most of off-the-shelf 2.4" props and 1103 motors.

Quick specs:
Weight: 3.2gm
Frame size: 90mm
Motor mount hole spacing: 9mm
ESC/FC hole spacing: 16mm
Motors: 1102/1103 recommended
Max prop size: approx 61mm (2.4")
Arm width: 2.34mm
Frame thickness: 2mm
Motor center hole: 4mm

Dave's comment: super light, best for los only.

Fast, lightweight 90mm frame with super narrow arms for minimal wind resistance.

This frame is very fast with Racerstar BR1103B 8000Kv or 10000Kv motors, a 2S 300mAh battery, 3020 props cut to 59mm and a BS06D 2.4gm 4 in 1 esc, or any similar lightweight esc. An even lighter esc is the TinyPepper2 at 1.3gm.

A pic of a recent build, trying out different motors and props. the Racerstars are smooth and efficient, arguably the best motor for this frame. Different props can give different performance characteristics, the 3020's cut down are often (but not always) the best all-rounder on high KV motors. A Nano-tech 2S 300mAh 45-90C is the best battery found so far.

This "true x" frame is cut so that the grain of the carbon fibre sheeting runs down the length of the arms, rather than the conventional layout which has the grain running at a 45 degree angle. This dramatically increases the strength of these super-thin-arm frames, and requires a different, less efficient layout for AP to cut the frame, and thus is more costly. We consider our frames to be premium and cutting-edge, and that the extra cost of these unconventional frames is justified.

For more information visit:
https://www.rcgroups.com/forums/showthread.php?2883082-Tweaky-the-people-s-frame-and-its-variants