If you take boxing classes once per weak mostly for body fitness then it means that you are a casual boxer, then you don't need to be worried. A normal pair of wrap and a pair of boxing glove will be sufficient for you Just buy the wraps and gloves which fit you perfectly which easily can be found in your local sporting goods store.
But these gloves are not much durable. If you participate in competitions or taking regular boxing classes for self-defense that means you are more serious boxer, then you need to pay enough attention to buy your boxing gloves and other equipments. Most of the boxers own a pair of training gloves who train regularly.
This type of gloves is more durable than the normal fitness gloves. Most of the boxers use one pair of glove for training and also for sparring. But it will be better if you buy two pair of glove for each (one for sparring and another for general trainings).
Gloves shouldn't be so tight that can cause restriction of movement and should be enough tight not to fall during the punches in air. Usually training gloves comes with Velcro strap which prevents fall of gloves during training.
Before buying winning boxing gloves it is also very important to decide the appropriate weight of the gloves. Only for bag work light weight boxing gloves will be better. Because of thick padding heavier gloves can't make much damage. For ironical practice heavier gloves are better option. Light weight gloves with thin padding can make more damage, that's why professional fighters use gloves of 8-12 oz weight.
Heavy gloves require more effort than the light weight gloves that's why heavy gloves increase strength of arms. Training gloves normally comes in a range of 14-20 oz in weight. Most boxers use the gloves of 16-oz, which is the standard weight of gloves. According to the professionals beginners should star with 14-oz gloves. 18-oz gloves are mainly used by the experienced fighters and the 20-oz gloves are used by some professionals during training.
According to professional boxers, serious boxers do have their own sense of appropriate size of glove they need. So you should have your sense of size that will be perfect for you But if you feel any doubt about the size, simply consult with your trainer. Normally each glove of particular weight comes in three different sizes which means if want gloves of 16-oz weight then you will have three different sizes (small, medium and large) to choose.
But you should also keep it in mind that best boxing gloves stretches with use So a appropriate new glove should be a little tight in fitting, that's why it will not fit perfectly in the first few weeks. Another important thing is to get the perfect measurement; you have to wear hand wraps at the time of buying gloves.
