キヤノン エクステンダーキャップ E II EF 1.4x & 2x テレコンバーター用フロントキャップ

I finally misplaced my original cap, and this replacement snapped on exactly as it should without any wobble. The plastic feels sturdy enough to stay put in my bag.

Finally, a cap that actually stays on without rattling around. The fit on my 2x extender is snug but not so tight that I have to wrestle it off, which is exactly what you want when swapping lenses in a hurry.

Finally, a proper replacement cap that actually fits snugly on my teleconverter without any wobble. It clicks on cleanly and stays put in my camera bag, which is exactly what I needed after losing the original.