in the preferred form of the invention a sleeping bag is provided as follows . the sleeping bag 1 is provided by providing a first panel 2 and a second panel 3 joined to the first panel around at least part of the edges thereof , each panel being for example of a size such as to form when joined a double sleeping bag as shown in fig1 . each panel is normally rectangular in shape . each panel 2 and 3 may be insulated , for example , in the known way , and one or both panels 2 and 3 may be waterproofed , in particular first panel 2 which when waterproofed should form the downward or underneath panel of the sleeping bag 1 in use . such waterproofing may be provided , for example , by providing a layer 4 of nylon or similar fabric on the outer surface thereof . thus the panel 2 may comprise the nylon or similar fabric surface 4 , an insulating layer 5 of any suitable insulating material and a further layer 6 to cover the insulating layer 5 if necessary . the second panel 3 may also be similarly constructed with covering layers 7 and 9 if necessary covering an insulating layer 8 . in the second panel 3 if desired the insulating layer may be dispensed with , and of course when an insulating layer is provided the insulation may be of such a type that the covering layers 7 and / or 9 may not be necessary . the sleeping bag may then be constructed , for example , by providing the upper panel 3 and the lower panel 2 , for example , by sewing the layers forming each panel around the edges thereof . in fig1 and 2 the panels are not shown as sewn along the forward facing edges which are intended to form the entrance to the sleeping bag , but this is for clarity only and normally sewing of these panels would be effected along these edges . the panels 2 and 3 may then be sewn together , for example , by the sewing line 10 which passes down the sides 11 and 12 of the bag and across the foot 13 . of course an opening must be left to a user to get into the sleeping bag 1 . connecting means are provided on or adjacent i . e . along at least the side edges 11 and 12 of the bag and preferably also along the foot 13 thereof , and the connecting means are preferably a zip fastener one half of which is connected down the side 12 of the sleeping bag and across one half of the foot 13 and the other half of which is positioned down the side 11 of the sleeping bag and across the other half of the foot 13 . thus the zip fastener may be positioned by the sewing line 10 also positioning the cloth part of the zip fastener between the bottom and top panels 2 and 3 before sewing . alternatively the sewing 10 may be effected by positioning the layers 4 , 5 , 6 , 7 , 8 and 9 or such of these as are being used , and the tab of the zip fastener and then effecting a single sewing around the sewn line 10 . it is apparent that the construction of the sleeping bag is such that the bag 1 may be folded , for example , longitudinally in a manner such that the side edges 11 and 12 of the sleeping bag are positioned adjacent one to the other . in this position the zip fastener may then be closed to join the adjacent side edges 11 and 12 and the two now adjacent halves of the foot 13 . this has the effect of forming a sleeping bag one half of the width of the sleeping bag shown in fig1 i . e . a sleeping bag as shown in fig2 . in this second arrangement of the sleeping bag , the first panel 2 forms an outer member surrounding an inner member formed by the panel 3 as shown in fig2 . thus a person wishing to use a sleeping bag as shown in fig2 would normally get into the sleeping bag in a manner such that he is surrounded by the inner member 3 i . e . the original top panel . suitable draw strings ( not shown ) may be provided along the top edge of the sleeping bag as desired . in the preferred embodiment of the invention the sleeping bag may be used as a double sleeping bag , i . e . such that two persons wishing to use the sleeping bag would sleep between the first and second panels , but if it is then desired to use the sleeping bag as a single sleeping bag , the side edges of the first and second panels are positioned one adjacent to the other and the connecting means , i . e . the zip fastener , could be closed . the person desiring to use the sleeping bag would then use the sleeping bag in substantially the known manner . thus it can be seen that a sleeping bag is provided which can be used as a single or double sleeping bag without the necessity of joining or separating single sleeping bags . this of course is advantageous and it is a particular advantage of the invention that the transition from a single to a double , or from a double to a single , sleeping bag may be effected in a speedy and simple manner .