1. A system for collecting biological fluids, comprising: a polymer sleeve, comprising: an elongated body that defines a first end, a second end opposite the first end, and a longitudinal central axis； a main passage through an elongated body parallel to the central axis, wherein the main passage passes from the first end to the second end, the main passage restricting the first hole in the first end and the second hole in the second end； the first part suspended above the first hole at the first end, while the first part borders the first initial passage aligned with the main passage, and the first part and the first end form an internal volume； a first ventilation hole partially limited by the first part, the first ventilation hole being different from the passages, and the first ventilation opening provides fluid communication of the internal volume with atmospheric pressure； and a second air vent partially limited by the first part, wherein the second air vent is different from the passages and the first air vent, and the second air vent provides fluid communication of the internal volume with atmospheric pressure. 2. The system of claim 1, wherein the main passage is aligned with the longitudinal central axis of the elongated body. 3. The system of claim 1, wherein the first initial passage is aligned with the main passage. The system of claim 1, which further comprises an outer shell of rigid material that forms an internal volume, while the elongated body is at least partially located inside the outside�1. Система для сбора биологических жидкостей, содержащая:полимерную втулку, содержащую:удлиненное тело, которое определяет первый конец, второй конец, противоположный первому концу, и продольную центральную ось；основной проход через удлиненное тело, параллельный центральной оси, при этом основной проход проходит от первого конца ко второму концу, причем основной проход ограничивает первое отверстие в первом конце и второе отверстие во втором конце；первую детал
