Maxspect R420r hanging kit screw

Hello and good day.

I recently purchased the R420r 160W 16,000K LED's and somehow
lost, misplaced or did not have 1 screw needed to use for the hanging kit.

Can I purchase 1 replacement screw or need to purchase 4 as a set?
I have attached a picture for correct identification.

pic #1

http://s141.photobucket.com/user/earthguy00/media/My%20stuff/20140426_0705091_zps5440ac89.jpg.html

pic #2

http://s141.photobucket.com/user/earthguy00/media/My%20stuff/20140426_0618181_zps91ec4568.jpg.html


Please advise.

thx.

Jo