Here's my 4. What should # 5 be?

[M.FREEZE]

Here are my four Benchmade Wilkins/Ritters.
What should I look for next? How hard to find are M4 Ritter blades?



From L-R:

Wilkins Black/Desert Tan G10 with CPM M4 blade-#306 of 500

Wilkins Blue Aluminum with CPM M4 blade-#317 of 500

Wilkins Lava Orange/Black G10 with Black S30V Ritter blade

Wilkins Swimming Pool Green G10 with stonewashed S30V Ritter blade