安全ピン
https://i.imgur.com/OcjsE38.jpg
https://i.imgur.com/zte080p.jpg
https://i.imgur.com/TyQprtq.jpg
https://i.imgur.com/iBwaq4R.jpg
https://i.imgur.com/C86DxtF.png
https://i.imgur.com/TAc66Bf.jpg