The missing word puzzle

This is a short passage from a newspaper article. The passage is about an object. The name of the object (which, as it is used here, is only half of the whole name) has been left out from all the places where it appears in the original article. Can you find out what it is?

"This is my own ********** ," says Olivér Nagy, showing me the inscription 'Olivér's **********'. I use this at competitions. Each contestant brings his own ********** after he has adjusted the tightness of the springs and the lubricant to fit his own hands. We use ordinary shop-bought **********, which we take apart and then file the internal mechanism. There are people who colour them, adding purple or pink sides, which they can recognize during a fast solve. I've changed nearly everything in mine - the radiuses, the spring, the screws and the washers - so it's well adjusted."

(The number of stars in the missing word does NOT correspond with the number of letters.)