A chemical and/or biochemical apparatus for receiving a plurality of reaction vessels in which chemical and/or biochemical reactions may take place, the apparatus comprising: a thermal mount of a thermally conductive material, the thermal mount having a plurality of wells for receiving the reaction vessels, an upper portion of each of the reaction vessels having a top opening sealed by a respective top seal; a thermal module thermally coupled to the thermal mount for thermally controlling the thermal mount; and a lid having a laminar structure comprising an outer cover, a thermally conductive heated plate having a laminar resistive heater layer applied to an upper surface of a thermally conductive plate for heating the thermally conductive heated plate, and a compressible foam layer arranged between the thermally conductive heated plate and at least part of the outer cover, and a locking structure, wherein the lid is fully removable so that it can be located and mounted to the rest of the apparatus in a substantially axial direction and is configured to be movable between an open position and a closed position, wherein, when it is in the closed position, the thermally conductive heated plate contacts the top seals of the reaction vessels when they are positioned in the plurality of wells, and the compressible foam layer is compressed between the outer cover and the thermally conductive heated plate so as to bias the thermally conductive heated plate against the top seals of the reaction vessels, and wherein, as the lid is moved from the open position to the closed position, the lid is configured to be movable in a direction to contact substantially simultaneously all the top seals of the reaction vessels when they are positioned in the plurality of wells, and wherein, when the lid is in the closed position, the locking structure locks the lid in the closed position. a thermal mount of a thermally conductive material, the thermal mount having a plurality of wells for receiving the reaction vessels, an upper portion of each of the reaction vessels having a top opening sealed by a respective top seal; a thermal module thermally coupled to the thermal mount for thermally controlling the thermal mount; and a lid having a laminar structure comprising an outer cover, a thermally conductive heated plate having a laminar resistive heater layer applied to an upper surface of a thermally conductive plate for heating the thermally conductive heated plate, and a compressible foam layer arranged between the thermally conductive heated plate and at least part of the outer cover, and a locking structure, wherein the lid is fully removable so that it can be located and mounted to the rest of the apparatus in a substantially axial direction and is configured to be movable between an open position and a closed position, wherein, when it is in the closed position, the thermally conductive heated plate contacts the top seals of the reaction vessels when they are positioned in the plurality of wells, and the compressible foam layer is compressed between the outer cover and the thermally conductive heated plate so as to bias the thermally conductive heated plate against the top seals of the reaction vessels, and wherein, as the lid is moved from the open position to the closed position, the lid is configured to be movable in a direction to contact substantially simultaneously all the top seals of the reaction vessels when they are positioned in the plurality of wells, and wherein, when the lid is in the closed position, the locking structure locks the lid in the closed position.