A lid assembly comprising: a lid comprising a rim for engaging an opening of a container, the rim defining a top wall and a side wall; a slider comprising a slider tab, a first positioning magnet and a second positioning magnet; the lid further comprising a middle wall extending below the rim, the middle wall having a first opening and at least one air vent, a third positioning magnet, and a fourth positioning magnet; and wherein the slider is configured to selectively provide a closed position by covering the first opening and an opened position by uncovering the first opening and the at least one air vent; wherein the first positioning magnet is configured to interact with the third positioning magnet to maintain the slider in the closed position and the first positioning magnet is configured to interact with the fourth positioning magnet to maintain the slider in the opened position; wherein the slider is reversible and symmetric and by reversing the slider the second positioning magnet is configured to interact with the third positioning magnet to maintain the slider in the closed position and the second positioning magnet is configured to interact with the fourth positioning magnet to maintain the slider in the opened position; wherein the slider further comprises a first clamping magnet and the middle wall comprises a second clamping magnet, wherein the first clamping magnet on the slider is configured to interact with the second clamping magnet on the middle wall to maintain the slider on the lid. a lid comprising a rim for engaging an opening of a container, the rim defining a top wall and a side wall; a slider comprising a slider tab, a first positioning magnet and a second positioning magnet; the lid further comprising a middle wall extending below the rim, the middle wall having a first opening and at least one air vent, a third positioning magnet, and a fourth positioning magnet; and a middle wall extending below the rim, the middle wall having a first opening and at least one air vent, a third positioning magnet, and a fourth positioning magnet; and wherein the slider is configured to selectively provide a closed position by covering the first opening and an opened position by uncovering the first opening and the at least one air vent; wherein the first positioning magnet is configured to interact with the third positioning magnet to maintain the slider in the closed position and the first positioning magnet is configured to interact with the fourth positioning magnet to maintain the slider in the opened position; wherein the slider is reversible and symmetric and by reversing the slider the second positioning magnet is configured to interact with the third positioning magnet to maintain the slider in the closed position and the second positioning magnet is configured to interact with the fourth positioning magnet to maintain the slider in the opened position; wherein the slider further comprises a first clamping magnet and the middle wall comprises a second clamping magnet, wherein the first clamping magnet on the slider is configured to interact with the second clamping magnet on the middle wall to maintain the slider on the lid.