A device for connecting a plurality of plastic microtubes accommodating glass fiber cables to a glass fiber distribution box, comprising: - a support body which can be attached to the glass fiber distribution box for mounting and dismounting and has a plurality of channels for receiving and completely guiding through a respective microtube; - at least one clamping device arranged in a channel for a tensile force absorbing fastening of the microtube to the support body; and - at least one seal additionally arranged in the one channel as a component separate from the at least one clamping device for sealing the microtube with respect to the support body; wherein the support body, the clamping device and the seal can be attached to the glass fiber distribution box as a mounting unit and can be removed; wherein the clamping device has a releasable locking mechanism which comprises an anchorage which allows the microtube to be inserted into the glass fiber distribution box interior and, when the microtube is actuated in the opposite pulling direction out of the glass fiber distribution box, engages with the microtube in a barbed hook manner, wherein the clamping device has a sleeve structure inserted into a respective channel of the support body, on the inner side of which the anchorage is provided which allows the respective microtube to be inserted in a yielding manner and has a plurality of elastically deformable, radially inwardly projecting claws which, when viewed, are inclined radially inwards into the interior of the glass fiber distribution box in order to stand up in a radial direction during a pulling movement of the microtube inserted into the clamping device. - a support body which can be attached to the glass fiber distribution box for mounting and dismounting and has a plurality of channels for receiving and completely guiding through a respective microtube; - at least one clamping device arranged in a channel for a tensile force absorbing fastening of the microtube to the support body; and - at least one seal additionally arranged in the one channel as a component separate from the at least one clamping device for sealing the microtube with respect to the support body; wherein the support body, the clamping device and the seal can be attached to the glass fiber distribution box as a mounting unit and can be removed; wherein the clamping device has a releasable locking mechanism which comprises an anchorage which allows the microtube to be inserted into the glass fiber distribution box interior and, when the microtube is actuated in the opposite pulling direction out of the glass fiber distribution box, engages with the microtube in a barbed hook manner, wherein the clamping device has a sleeve structure inserted into a respective channel of the support body, on the inner side of which the anchorage is provided which allows the respective microtube to be inserted in a yielding manner and has a plurality of elastically deformable, radially inwardly projecting claws which, when viewed, are inclined radially inwards into the interior of the glass fiber distribution box in order to stand up in a radial direction during a pulling movement of the microtube inserted into the clamping device.