What does this mean?
 

Whenever aiming at a tank with armour peircing rounds, this comes up.

What does the number and colour represent?

http://img684.imageshack.us/img684/4...esthismean.jpg

Im not 100% sure but my guess is the number in the colored box is your max milimeters of armor your gun can penetrate at the range. The white number is your range from target and the color is: Red...no possible penetration, Yellow, possible penetration or damage and green is supposed to be Guarenteed penetration but id take it w/ a grain of salt.....those colors and numbers from what ive seen dont mean a whole hellva lot. Ive had 115 Green Penetration on a Tiger who has 100mm of armor on its front and bounced so yeah. Then ive had like 80 Red on a Pzr IV front and blown it into next year. I guess those numbers are more a guideline then anything else. I prefer them off haha

The numbers don't take into account the angle of the armor. For example, if you were to shoot at where the gun in the picture is, the round would just get deflected upward and in few cases hurt another unit. But with a 88mm round it has a chance of beating the armor angle. Now, if you were shooting indirect fire and the round came from above and hit, with a 88+mm it would damage the tank greatly, but most rounds that use indirect fire are not AP rounds.

The numbers are not exact, just a guideline. The only number 100% correct is the range.