The basic front print t-shirt is combed cotton, 180 gsm. It is a kind of special cotton. It has been subjected to a specific treatment before being spun into yarn. It gives the best results and is made of soft, cool, and comfortable regular cotton. GSM (grams per square meter) is a measure of fabric weight. It describes the weight of the tee. For lightweight/summer tees, look for a GSM of 160 or under. For heavyweight/winter tees, look for a GSM of over 180. For versatile/all-season tees, look for a GSM between 160 and 180.
But this kind of GSM depends on country-wise requirements so that you can customize your T-shirt to your requirements.