Abstract-Coverage in 3D wireless sensor network (WSN) is always a very critical issue to deal with. Coming up with good coverage models implies energy efficient networks. K-coverage is a model that ensures that every point in a given 3D Field of Interest (FoI) is guaranteed to be covered by k sensors. In the case of 3D, coming up with a deployment of sensors that gurantees kcoverage becomes much more complicated than in 2D. The basic idea is to come up with a convex body that is guaranteed to be k-covered by taking a specific arrangement of sensors, and then fill the FoI with non-overlapping copies of this body. In this work, we propose a new geometry for the 3D scenario which we call a Sixsoid. Prior to this work, the convex body which was proposed for coverage in 3D was the so called Reuleaux Tetrahedron [1], [2]. Our construction is motivated from a construction that can be applied to the 2D version of the problem [13] in which it implies better guarantees over the Reuleaux Triangle. Our contribution in this paper is twofold, firstly we show how Sixsoid gurantees more coverage volume over Reuleaux Tetrahedron, secondly we show how Sixsoid also guarantees a simpler and more pragmatic deployment strategy for 3D wireless sensor networks. In this paper, we show the construction of Sixsoid, calculate its volume and discuss its implications on the k-coverage in 3D WSNs.