They measure 6mm and have a scant 1mm top loop, so 20 gauge wire or jump rings will fit through.They do not contain nickel or lead.
Each listing is for 100 in YOUR PICK of finish:
The antique copper bell is pictured with a matching jump ring. They are not included in THIS listing but you will find listings in my Etsy Shop that include them.
I carry a variety of BELLS findings 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#!