UPDATED - with an elasticated sling! Specially designed for trans guys, the Boxer STP/Packing Underwear has a sewn-in interior hanging pocket to support STP and packing devices. The secondary U-shaped interior panel gives you the option to position the shaft to the left or right for a natural hang. The 2nd gen of our STP/Boxer has an updated sling pocket featuring an elastic panel that will stretch to different sizes allowing for greater compatibility. This new design also allows the STP or Packer to sit inside or outside the interior pocket depending on preference - and still has the operable front opening to pull shaft out when needed.