The PD blocker is a USB-C Power Delivery firewall. It provides over-voltage protection and prevents power delivery communication in order to protect your device.
The HDMI firewall prevents devices from hacking HDMI equipment, and vice-versa
The USB-A to USB-C (aka. USB-AC) cable tester identifies which features a USB-A to USB-C cable supports.
The USB bug detector identifies USB type-A cables (or devices) with integrated circuits.
The USB-C cable tester shows which features a USB-C to USB-C cable supports.
The micro-USB cable tester verifies if a USB 2.0 cable with micro-B plug can be used to transfer data, or just for charging.