What are the specifications of this type of LED strip?
These are COB led modules. As described by Digikey: 


  LEDs compete with traditional lighting sources in a number of ways, including greater energy efficiency, longer lifetime, and smaller size. However, the one drawback that has vexed many lighting designers is cost, which is a key reason why LED manufacturers continue to innovate to improve economies of scale. One of the newest packaging solutions designed to help lower costs is chip-on-board (COB) light source modules, in which the LED chips are in the form of a semiconductor chip that is neither encased nor connected but directly mounted onto a PCB or, more generally, a substrate. This packaging style also provides several related benefits, such as greater design flexibility, better light distribution, and simpler manufacturing processes. 


There is no set standard voltage, current, or form factor. It depends on the chips used and how they are wired internally. Based on what you found, these seem to be 1 Watt modules. I wouldn't push them past 9~10 Volts unless you want to sacrifice one. But heat sink them before anything else!. These are meant to be mounted on Aluminum channeling. Running them without a heatsink at full current draw will kill them quick.

Of course, these could also be 24V 3W or 5W modules, or 10V 0.7W to 3W or 120V or anything.