Klein's Hourglass

The item is a malformed Hourglass:

It is an unusual item, the enchanter "Felix Klein" seems to have attempted to cast the haste spell onto one half of the bottle and the slow spell onto the other, this is of course, impossible. The process warped the hourglass into its non-symmetrical form, in fact the glass itself seems to be moving ever so slowly... The hourglass seems to cast the slow spell and the haste spell at the same time when it's used an unintended side effect. The hourglass seems to cast the spell inward and outward rather than the top or the bottom.

If the haste spell is cast on the outside, to the user, the slow spell is cast inside, causing the sand to fall ever so slowly, it seems to not lengthen the duration of the haste spell, however the sand rather than taking one hour to reach the other side, takes many hours (One use per long rest), also as long as the sand falls, a concentration check is unnecessary.

If the slow spell is cast on the outside, through the user to other targets, the haste spell is cast inward; sand inside the bottle falls quickly, lowering the slow effect to 12 seconds, (2 turns).

However since the sand falls quickly, the item is ready to be flipped again in 10 minutes rather than a regular 1 hour,, also as long as the sand falls, a concentration check is unnecessary.

It is unclear how to choose which spell is cast, if it is possible at all, one side may be smaller than the other, but looks are deceiving.

The bottle is slowly moving, the "top" is bending sideways and eventually will touch the side of the hourglass, then go into it, then reach the other side, then open making a Klein bottle. Once the transition is complete the user can choose which spell to cast when they want and the effects of the spell have normal durations. The unfortunate part is once it's open all the sand will fall out, a player can use one turn to refill the bottle but it uses their entire turn.