baby shower gifts

how would i write on my invitation about gifts ? we haven’t sent out a registry because we did all the math and decided with how much we’ve been saving through out the pregnancy and even before, we would be able to buy all the bigger necessity items like crib, bassinet, travel system, etc. ourselves with no problem we also didn’t want anyone feeling pressured to buy expensive gifts. instead we wanted to specifically ask that if people wanted to bring gifts to the shower to only bring diapers or wipes or a gift card. and instead of sending a card with their gift i saw someone ask they buy a baby book and write a message in it instead. but im not sure how to put that without sounding demanding lol