Just for the record the bigger one is Tillandsia caput-medusae and the smaller one is tillandsia bulbosa.
Unlike the other common types these are bulb appearing type which by my experience can be difficult and tricky - they can rot easily compared to the rosette types.
Watering must be carefully administered that it must dry off immediately as they can rot if they stay wet throughout the day. Therefore placing them in a good windly, air movement location is very ideal for them or another option of receiving good bright indirect sunlight for them to dry off on daily basis.
There are many varieties of both of this kind but I'm just keeping these two types for variety sake.
It is a slow growing plant and may get easily damaged if handled roughly therefore place them in a permanent location as they don't get stressed and avoid removing them often.
Some growers advise the gardeners to often submerge them in water and turn them upside down to drain off the excess water - I find that too tedious and requiring too much effort. It is best to tie them up - side ways and water them daily if the conditions are right.
Do check out my detailed information on how I care for my Airplants on my link below:
Care & Cultivation on Airplants