O'Neill Heat 3mm Split Toe Boot Men's Surf O'Neill 3MM Heat Split Toe Neoprene Bootie at SwimOutlet.com O'Neill Mens Heat Round Toe 3mm Booties Oneill Epic 3mm Round Toe Wetsuit Boots Heat Ninja 3mm Split Toe Boot from ONeill! Kitemana.com. Keep your feet warm with O'Neill's Heat Round Toe Booties. Built rigorously to endure the elements and keep out water, these booties are an easy pick for round toe bootie lovers. Easy to put on and take off and completed with an ankle strap to keep them tight, it's an easy pick in our book. We recommend sizing close to your shoe size and sizing down a size to ensure they are snug but not uncomfortable.