Dear Sir,Due to the raw material cost of XX company increasing, we have to increase the price of below models for 5% base on the original price from now on：Model ABCDEModel EFGHIThis is a tough decision and we understand this will bring you inconvenience, but 5% is our best effort to keep balance between our customers and covering our cost.We greatly regret any inconvenience it may cause, and hope we can receive strong support from your side.Thank you very much. I'm available for any questions you may have.Best regardsXXXXXX以上是比较谦虚的版本，如果厂方没有这么弱势，可以写的强硬些。
刀刀吹雪
