The description of the Eva Air Personal Item is below, and does not matter which class seating:

Personal Item (Carry-on Item)

In additional to free hand-carry baggage, each passenger may carry one piece of free personal item for all classes with dimension 40 x 30 x 10 cm /16 x 12 x 4 in or total linear dimensions 80 cm/32 in or an item of similar size (subject to local country specific restrictions, if any). These dimensions include wheels, handles and side pockets. If your item exceeds the total dimension of 80 cm/32 in, it will be counted as part of standard hand-carry baggage allowance. You will then be required to check in either the hand-carry bag or the personal item.