Hard Disk Drives (HDD) are mechanical magnetically recording based devices.

Solid State Drives (SSD) are eletrically based data recording devices. 

R.A.I.D. stands for Raid Array of Independent Disks. A simple interpretation of the technology is storing data on multiple disks instead of one disk with the goal of achieving redundancy and fault tolerance". We recover data from all R.A.I.D. configurations, where the most common are R.A.I.D. 0, 1, 3, 5, 6, 10, 50, 60.

A pen USB flash drive is an electrically based recording device that has a USB interface. 

External Drives are portable peripheral devices. From a technological perspective, they are basically a regular HDD or SSD enclosed in a casing that may have a single interface, such as the popular USB, or in combination with other interfaces, such as Firewire 400/800, E-Sata and Thunderbolt. Beginning with 2014, technological advancements allows for wireless connectivity.

We perform data recovery on Compact Flash and SD Cards like devices are. They are electrically based data recording devices. From a design perspective, these types of storage are very complex, therefore if the device is severely degraded or damaged, then recovery could be quite difficult.

We perform data recovery on optical media storage, such as CDs and DVDs. These types of storage are simple in terms of design, however if the media is severely degraded, then recovery could be quite difficult.