To know how many Kg from manila to Beijing both business and economy class

Hello Sir/Ma,
Am a travel agent from Nigeria, i booked Air China for my clients from Manila to Beijing both business and economy class and would like to find out the baggeg allowance ie how many kg they should have as they demand to know. I will be grateful if i can get this information to pass it to them because its very nessecary for them to know.
Regards,
Jennifer
MD/CEO