What are the letters of Tarqeek?

What are the letters of Tarqeek?
To know the letters of tarqeeq (attenuation),  you need to first know the letters of tafkheem (velarization).  Tafkheem is defined as : It is a heaviness that enters the body of the letter, so that the mouth is filled with its reverberation (echo).
There is a group of seven letters which always are read with tafkheem, they are the letters in the group: .   There are a few letters which sometimes have tafkheem and sometimes have tarqeeq, they are: the lengthened alif, the and the

All of the remaining letters of the Arabic alphabet are always read with tarqeeq, meaning they are light and the mouth does not fill with an echo when you read them.