Can't get much thinner walls than this type. My Yamaha generator came with one in the box.

Emgo Spark Plug Socket Wrench 18mm 18 mm Honda Yamaha Kawasaki Suzuki KTM | eBay

Emgo Spark Plug Socket Wrench 18mm 18 mm Honda Yamaha Kawasaki Suzuki KTM | eBay
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