Because the pouches are removable, you can easily change them to equip yourself for different situations. Their inexpensive price allows you to fully trick out your T.
How many magazines can the pouch hold?
The manufacturer does not really say but my two S&W M&P .40 cal, 15 round magazines fit just fine. You can also carry smaller mags, such as a 7 round single stack.
What can I carry in the accessory pouch?
Many items such as a full sized BlackBerry phone, iPhone, pepper spray, most sized wallets, knives, badges, folding money, etc.
What sizes do they come in?
Only one size is available at the moment.