Loincloth is pure metallic destruction. Whereas most sludge is content to milk riffs constantly, Iron Balls of Steel stays true to its name and offers up 16 densely constructed instrumental tracks. Running crop circles around most bands with a hazy stoner sound, they are surprisingly technical and ever-shifting. “Underwear Bomber” explodes with a slew of groovy riffs wrapped in distorted thumping bass, showing out of the gate that this album truly has iron balls of steel. “Trepanning” branches off into a more doom-and-death metal-tinged approach to sludge. No song stays on a riff for more than a few bars; each showcases the off-kilter drumming of Steve Shelton and his intricate interplay with guitarist Tannon Penland, accompanied by the loud, distorted bass of Cary Rowells. The march-like tempo of the gargantuan “Theme,” a fitting title, assaults the listener with angular riffs over serpentine twisting drums, accented by warbling bass, making for an intense headbanger. While vocals might have helped, the absence doesn’t detract from this new breed of progressive, stoner groove metal.