Lightstrip Plus RGB extension cord

Hello, I have a 2 meter lightstrip plus rgb and 2 extension strips, I want to put 2 meters on one side of a furniture and the other 2 meters extension on the other side of the furniture.
I bought an extension cable to join 4 pin rgb led strips, but it does not fit, the pin size is different. How can I do? What type of pin connection do the lightstrip plus strips have? they are smaller than my extension cord.
Can somebody help me? Thank you.