As the title suggests, it's a simple black radar which is transparent. It's not pixel transparent, just transparent.
It has two variants, one with a fov cone, and a plain circle. You can see more details in the screenshots. Remember to use cl_radartype 1 or the radar might not work at all!
The radar could probably be any color, but i think black works the best. The transparency can also be changed and multiple elements can have different alpha. If anyone's interested I can make a guide or something ;)
In the .zip archive, choose the version you want and then open its folder.
Copy the "sprites" folder to your game's cstrike folder.
Select Cut and Replace.
Launch your game, open the console and type cl_radartype 1.
You can also set it like this:
Open Options > Multiplayer > Advanced > Radar type > Solid
If you have problems after restarting the game, add cl_radartype 1 into your config as well.