Possible Clues:

• There's 2 x 10 in, and that's about the size of it
• And it's about twice ten, and that's about the size of it
• How much the camper emerges?
• That's how much comes out from under the canvas
• A cake; last word of Macbeth
• Range times 10 in case of eyesight
• That's how much a camper might get out of this
• Amount of old wine
• This has scope and is about 1010
• Scope to get one out of the canvas