Our Mission: To protect, preserve and promote the natural integrity of Radnor Lake through land acquisition, environmental education and park support.
Chains up to 12 mm thick are generally portable: you can carry them around on your bike every day. The long ones will be really heavy though, so please check the weight. Above 12 mm the chains are more suitable as stationary locks: you would leave them wherever you lock your bike for long periods of time.
1 Each of the heavier pennies weighs $2.50 + 0.61$ grams. 2  So if there are $x$ of the heavier pennies in the roll then the total weight of pennies in the roll is $$ 50 \times 2.50 + 0.61x. $$ 3  This is the same as $125 + 0.61x$. 4  So if the total weight of the roll is $138.42$ grams then we have $$ 125 + 0.61x = 138.42.