FTS rocks but don't put it on anything with large recoil. Say like 12g. Anything like a 223/6.8/x39 powder or less it's very nice. The 4x is out there as a specail order as 3x & now 5x is the norm. The wieght is not bad and the glass is great although the chinese nock-off's are almost as good.
Here is a link discribing that the 4x is now discontinued;
http://www.ar15.com/forums/t_2_419/196635_Blowout_on_Eotech_Magnifiers___Eotech_4X_FXD_4x_Fixed_Magnifier__Not_Flip_To_Side__FTS__YET_____599.html