To build this you will need a 40x40x10 12v fan, female DC power socket, vertical slide switch and HEPA filters. Links are below
40mm fan: Noctua NF-A4x10 FLX, Premium Quiet Fan, 3-Pin (40x10mm, Brown) : Amazon.ca: Electronics
Female DC power socket: uxcell A15012900ux0190 10 Piece 3 Pin PCB Mount 5.5x2.1 mm Female DC Power Jack Socket Connector : Amazon.ca: Electronics
Vertical Slide Switch: Aexit 10 Pcs Networking Products x 3 Pin 2 Position 1P2T SPDT ON-Off Miniature Panel Vertical Switches Slide Switch : Amazon.ca: Electronics