Intrapulmonary Percussive Ventilation machine. It's like a big green nebulizer that shoots saline (salt water) into your lungs in short bursts that also stimulate vibrations. Sort of like vest meets hypertonic super combo, and can be done with either HTS or ragular sterile saline. It's typically very effective, but some people/docs are scared of it because of the risk of pneumothorax and/or bleeding (it's intense, esp at high pressures).
I have an IPV, Acapella, Flutter, percussor and a vest. I know, spoiled for choice for sure. I used to do the IPV several times a day, now I mainly do the Vest, always at least 2x a day for 30 mins each. I sometimes add an IPV and the Flutter/Acapella combo is travel only. The percussor I only use to target a specific area in my lungs.
The reason I have so many machines is really just luck through the years. My doctor put me on the IPV after I started showing FEV1 decline, and I know it's typically considered to be a more hardcore treatment. But my doctor is fairly open - she lets me pick between methods of airway clearance because she feels I know what's most effective for me.