Please note the size variants is in reference to the base size, not the tillandsia. 

Tillandsia (also know as air plants) are fun and easy to grow! Tillandsia is the largest genus in the bromeliad family, accounting for approximately 550 of the over 2,500 species of bromeliads. They are native to the warmer climates of the Americas.

Care:
Air plants do exceptionally well in outdoor environments. A screened porch or pool patio would be the most likely areas to find the bright filtered light conditions that Tillandsia love. If your Tillandsia's are going to be in your home or office, care must be taken to provide enough light and correct moisture to maintain a healthy plant. A South, East or West window would be best. Bright light or filtered sun is recommended. Indoor tillandsia's should stay healthy with a watering schedule of 2 to 4 times a week. However, it may be necessary to water more often due to dryer, less humid air caused by air-conditioning or heating. Plants grown in humid outdoor environments should be watered 2 to 3 times weekly. In dryer climates, more frequent watering may be necessary.