This machine certainly fits the term travel size. Weight is very reasonable too. This review is based on a 9 day trip with 8 nights use and a following addition to the accessories.
If you have an interest in these travel machines you probably have watched videos about their noise. I did, and not one are even close to what they do in actual use. This machine is not too loud when you hook it up and let it blow out of the mask. But MUCH louder than my home unit. The problem is that it really increases noise when you inhale. This is where the online videos are completely misleading! I cannot run this on the EPR 3 setting as the noise is unbearable. It makes a very high pitched chirping sound as it ramps back up. On setting 2 it is ok. If you inhale sharply it makes a LOT of noise. So, once you settle down it should be ok? No, not as delivered. There is a huge difference in noise as you inhale. No matter what. As delivered, this HDM Z1 is all but unbearable for the user, and if you had a partner with you they could likely not sleep without ear plugs. With the mask on there is one other issue. It is almost like the tubing is transmitting the noise directly to you. I wear a P10 mask and I can hear the airflow in it at a level that kept me awake. Here is a pic of the machine and hose out of the box.

This 4 foot long hose that comes with it is extremely stiff. I never got it to straighten out and stay that way. If leaving the unit on a nightstand, 4' might be just fine. But I had to put this on the floor to get away from some of the noise. Hose is a very poor part. The connector into the machine seems to be something to be careful with. Ok so far. I ordered several of the moisture exchange units to put between the hose and the mask. Brought 3 with me on the trip. I used them, I don't know how well they work that far away from the mask. I will try without them next. They are really cumbersome as they make the hose harder to move around with. HOwever, they do act as silencers! I put one on the outlet of the machine and the noise reduction was noticeable. Two days after I got the machine, a travel cpap hose I had ordered arrived. What a difference in noise it made! Less noise coming out of the machine, but most importantly no noise to the mask from the internal airflow.
Don't plan on being too happy with this as it is delivered. More on that with the next post. BUT....it is a travel machine and the comparison with the ResMed airsense 10 autoset carrying case says a LOT!

I did find the machine reasonably easy to set up and change parameters on.