style A

S size 29cm(bottom length)*41cm(height)*14cm(bottom thickness),advising for grade 1-3
L size 32cm(bottom length)*45cm(height)*16.5cm(bottom thickness),advising for grade 3-6


style C

S size 25cm(bottom length)*41cm(height)*16cm(bottom thickness),advising for grade 1-3
L size 28cm(bottom length)*45cm(height)*19cm(bottom thickness),advising for grade 3-6

Maybe with 1-3cm size error.