With a more rectangular shape, K-style gutters are also a popular option for both homeowners and business owners. While half round gutters curve like a semi-circle, K-style gutters are flat on one side, and can be nailed directly into the fascia board. K-style gutters mimic colonial style crown molding and come in many different sizes, lengths, and colors – providing many options to choose from and work well with any home or commercial building because of their versatility.