They measure 25mm and have a 2mm top loop, so even large gauge wire or jump rings will fit through!
Your choice as to what finish you want.
I carry a variety of BELLS here in my Etsy shop. Click here to see them: http://www.etsy.com/shop/UnkamenSupplies/search?search_query=bells&search_type=user_shop_ttt_id_5613242&shopname=UnkamenSupplies
Would you like to hear them? Check out this Video- (copy and paste to a new browser tab!) http://www.youtube.com/watch?v=xqubJstQL4Y&list=UUv8W2ApHlD371FRiT6rtHrw&index=1&feature=plcp#!
Questions? Contact me.