The best old saying is, never leave each other, or long trunks together. If you don't want old sayings, you can carve quotations like "It's very kind of you" or "Forever and ever". If engraving is expensive, you can engrave letters at the beginning of his name if you charge by the number of words. Of course, if it is a gift to commemorate a special event, you can carve something about it. For example, birthday: H-B; Doctoral degree: Dr. XXX; ; Love anniversary: XXXloveXXX. If you have a novel idea and can express your information in short words, he will certainly like it.