For the Men's Style we use 'Gildan Performance Sleeveless T-Shirts' which offer two unique properties: Aqua FX which disperses moisture and fresh care which fights odour, making these the perfect gym vest.
 
Crew Neck
Sleeveless 
Colour: Royal Blue
100% Polyester jersey knit
 
Men's / Unisex Size Guide:
S 34/36" M 38/40" L 42/44" XL 46/48" 2XL 50/52" 3XL 54/56" 
 
For our Ladies Fit style we use 'AWDIS Girlie Cool Vests' which are also very nice quality and discribed as being 'lightweight and breathable'. It has a racer back fit and a curved back hum for extra comfort.
 
Girlie fit
Racerback style with self-fabric binding around neckline and armholes
Curved back hem for added comfort
 
Ladies Fit Size Guide:
 
XS - 8 , S - 10 , M - 12 , L - 14 , XL - 16