Shaker accessories include clamps and straps for securing lab containers, foam inserts for test tubes and microplates, tube holders, various drive shaft attachments, and platform pads. A flask clamp is most commonly used with Erlenmeyer flasks, and may be designed to hold single or multiple flasks. Flask clamps are available for different flask sizes, and in materials such as stainless steel, aluminum, and PVC (polyvinyl chloride). Some metal clamps are fitted with a spring for an improved hold. To avoid scratching labware, a PVC flask clamp may be selected. A tube holder may accommodate one or more tubes, and is available in designs for various tube sizes and types.