Our Knotty Alder Interior Doors with 2 panel V Groove arch top panel door design in 6' 8" and 8' 0". Our Rustic Interior Doors come prehung as interior single doors or interior double doors with stain/paint-grade jambs or solid knotty alder jambs with hinges and bore options. Interior Knotty Alder bi-folds with v-groove panels and track hardware.