Guide to Mac, iPad, iPhone ports: Lightning, USB-C, Thunderbolt & more | Macworld
Sabrent Premium 4-Port USB 3.0 Hub for iMac (2012 and later)
Aluminum alloy usb 3.0 hub 3 port adapter splitter with SD/TF Card Reader for iMac 21.5 27 PRO Slim Unibody computer
Review: 21.5-inch 2012 iMac takes two steps forward, one step back | Ars Technica
Amazon.com: Aluratek USB 3.0 Port Extender for iMac (AUHM0301F) : Electronics
Mac accessories Archives - Connecting Point
Adding USB3.0 to late 2009 iMac (11,1) | MacRumors Forums
USB-C Clamp Hub for 24-inch iMac
increasing USB ports on iMac late 2012? | MacRumors Forums
OWC Envoy Pro USB 2.0/3.0 Enclosure for... at MacSales.com
iMac (21.5-inch, Mid 2011) - Technical Specifications
AliExpress
Satechi USB-C iMac 2017 Clamp Hub Pro Multi-Port Adapter - Silver
Wizplat iHUB WIZ-UC70IMAC for New iMac 7-in-1 USB-C Clamp Hub USB-C USB3.0 HDMI 302706896209 | eBay
Amazon.com: SABRENT Multi Port iMac Hub with Front Access USB Ports, SD/Micro SD Card Reader, 3.5mm Headphone Jack and Rear HDMI 2.0 Output (iMac 2017 to 2020) (HB-SIMC) : Everything Else
iMac 21.5 -inch (Retina 4K) 3.0GHZ Quad Core i5 (Mid 2017) 8GB 1TB – Coretek Computers
Amazon.com: Sabrent Multi-Port iMac Hub + USB 3.0 and USB Type-C OTG Card Reader : Electronics
iHouse - Apple Authorized Reseller | Rocketek USB 3.0 Aluminum 4 port hub for iMac 2012-2017
