Promotional sweater vests are a smart business investment to boost your advertising campaign. Custom slipovers are sleeveless sweaters, or casual vests designed to keep the user warm. Common materials include fleece, polyester, and cotton. Personalized sweater vests are useful as employee uniforms, especially for outdoor workers as it traps heat during the cold season. You can also deliver printed sweater vests to customers and business partners as an appreciation gift.