‘Filshie’ Clips are made from titanium lined with silicone. They measure 14 mm x 3.4 mm x 4 mm.
They do contain metal so will show up on X-Rays, but they are reported to be non-magnetic so certain types of scan should be safe, however it is probably best to mention the clips in the event of a scan.
This picture of a Filshie Clip is from the blog ‘Post Tubal Ligation Syndrome is real’
Hulka clips became available in the 1970s. The Hulka clip is a small, gold plated stainless steel spring loaded clip measuring 13 mm x 26 mm x 2 mm. When the clip is placed across the fallopian tube, it is closed and a small spring holds the clip firmly in place.
It has been reported that gold in the clips may cause allergic reaction “A case is presented in which the gold covering the Hulka clip resulted in an allergic reaction, evidenced by sterile abscess formation and resulting in exploratory laparotomy for removal of the Hulka clips, sterile abscess, and resultant adhesions. … It would appear that careful screening for gold allergy should be undertaken before tubal sterilization with Hulka clips.”
Please note: These two types of clip are not the only devices that have been / are available for blocking the fallopian tubes, but these are the ones most commonly referred to in literature.