Phaser Box is built around a series of Low and High pass filters in cascade to imprint that notched phasey sound.
Phaser 2/8 is built around the classic All Pass filter design with selectable phaser stages between 2 to 8.
Both includes some features such as a selection of 5 different waveforms. Sine and Triangular are most used in traditional phaser units for that smooth modulated sound. Saw, Square and Random are more suited for a rhythmical feel. A Wave invert and a Phase adjust knob are also included (contributing to a stereo spread feel).