The wheels, usually made of polyurethane, come in many different sizes and shapes to suit different types of skating. Larger sizes like 65-90 mm roll faster, and also move more easily over small cracks in pavement. Smaller sizes like 48-54 mm keep the board closer to the ground, require less force to accelerate and produce a lower center of gravity, but also make for a slower top speed.
Between 1850 and 1900, sweatshops attracted the rural poor to rapidly-growing cities, and attracted immigrants to places like East London, England and New York City's garment district, located near the tenements of New York's Lower East Side. Wherever they were located, sweatshops also attracted critics and labor leaders who cited them as crowded, poorly ventilated, and prone to fires and rat infestations, since much of the work was done by many people crowded into small tenement rooms.
