hello I would like to make new digger design,but need answer what type of diggers in USA parks people can use. I know from posts in some places shovels forbid ed and people use small like minelab hand held knife -digger. my question is what is the border line between small shovel and one hand held digger? it should be hand held operating? or size? not bigger like 10 inch, or something else? thank you for all answers Stasys